Novel nucleic acid isolated from Tetrahymena which codes for a triterpenoid cyclase, its production, and use

ABSTRACT

The present invention relates to nucleic acids isolated from Tetrahymena which code for a ciliate-specific triterpenoid cyclase. The inventive nucleotide sequences and the polypeptide sequences derived therefrom demonstrate a surprisingly minimal sequence identity to known isoprenoid cyclases. The invention also relates to the use of nucleic acids for the regulation of triterpenoid cyclase expression in a host organism, as well as the targeted knockout or repriming of the triterpenoid cyclase gene. As a result of the altered expression of the triterpenoid cyclase, it is possible to modify and enrich the levels of multiple unsaturated fatty acids in the host organism.

FIELD OF THE INVENTION

[0001] The present invention relates to a triterpenoid cyclase (tetrahymanol cyclase) isolated from Tetrahymena, its coding nucleic acid, its production, and use.

BACKGROUND OF THE INVENTION

[0002] The inventive triterpenoid cyclase catalyzes the formation of tetrahymanol from squalene by a direct cyclization of squalene (Capsi et al. (1968) J. AM. CHEM. SOC. 90:3563-3564; Abe et al. (1993) CHEM. REV. 93:2189-2206). The triterpenoid cyclase also recognizes oxidosqualene as a substrate (Abe & Rohmer (1994) J. CHEM. SOC. PERKIN TRANS. 1: 783-791). In addition to pentacyclic triterpenoids, the squalene tetrahymanol cyclase also catalyzes the formation of tetracyclic triterpenoids (Abe & Rohmer (1991) J. CHEM. SOC. CHEM. COMMUN. 902-903). Tetrahymanol (or gammaceran-3-ol), which is derived from isoprene, is a member of the isoprenoid class. Isoprenoids play an important role as phytohormones and carotenoids, and as components of chlorophyll, ubiquinone, plant resins, oils, and latex. As steroid hormones, isoprenoids effect important functions in animals. The formation of tetrahymanol can be reprimed in Tetrahymena by adding sterols, such as cholesterol (Conner et al. (1968) J. PROTOZOOL. 15:600-605; Conner et al. (1969) J. BIOL. CHEM. 244:2325-2333).

[0003] Isoprenoids are also important components of bacterial and eukaryotic membranes. Similar to hopanoids and sterols (such as cholesterol), pentacyclic triterpenoid has tetrahymanol membrane-stabilizing properties (Conner et al. (1968; 1969); Poralla et al. (1980) FEBS LETT. 113:107-110). By restricting the fluidity of the lipid acid residues of membrane lipids, a condensed (membrane-solidifying) effect is achieved above the phase transition temperature; while below the phase transition temperature, the fluidity of the membrane is increased, thus preventing the optimal close packing of fatty acid residues. In addition, the membrane fluidity depends on the fatty acid composition of the membrane lipids. The fluidity of membranes increases in proportion to the levels of unsaturated fatty acids. With temperature changes, organisms are able to regulate the fluidity of their membranes, for example, via the fatty acid composition. Below the phase transition temperature, isoprenoids and unsaturated fatty acids increase the membrane fluidity via a synergistic effect. The inhibition of the synthesis of the cyclic triterpenoids alters membrane stability. This reduced membrane fluidity can be compensated by an increased proportion of polyunsaturated fatty acids (PUFAs) in the membrane, i.e., the content of PUFAs can be increased by inhibition of the triterpenoid cyclase.

[0004] The targeted modification of the composition of the fatty acid spectrum by means of gene technology for the commercial production of special fatty acids or oils is described in Napier et al. (CURR. OPIN. PLANT BIOL. (I 999) 2:123-127); Murphy & Piffanelli (SOC. EXP. BIOL. SEMIN. (1998) Ser. 57 (PLANT LIPID BIOSYNTHESIS) 95-130); and FACCIOTTI & KNAUF (In: ADV. PHOTOSYNTH. 6: LIPIDS IN PHOTOSYNTHESIS: STRUCTURE, FUNCTION AND GENETICS. Siegenthaler & Murata (eds.) Kluwer Academic Publishers, Netherlands. (1998) 225-248). Thus, the modification of fatty acid composition can be regulated by altering the genes that code for enzymes which directly participate in the fatty acid synthesis, such as desaturases. However, it has been reported that the level of PUFAs in transgenetic organisms was relatively low (Knutzon & Knauf (1998) SOC. EXP. BIOL. SEMIN. SER. 67:287-304).

[0005] The knockout or repriming of the gene that codes for triterpenoid cyclase and the resulting deficiency of tetrahymanol may influence membrane fatty acid composition. However, the modified membrane fluidity can be balanced by the production of unsaturated fatty acids.

[0006] Although the triterpenoid cyclase protein from Tetrahymena is known and has been purified (Saar et al. (1991) BIOCHEM. BIOPHYS. ACTA, 1075:93-101), it had not been possible to clone the gene for triterpenoid cyclase from Tetrahymena (dissertation of Michal Perzl (1996) at the Faculty of Biology of Eberhard Karls University Tübingen). In previous studies, the gene sequence of triterpenoid cyclase could not be determined by sequencing the purified protein, PCR with degenerative primers, or hybridization with heterologous probes.

[0007] The present invention relates to nucleic acids isolated from Tetrahymena which code for a ciliate-specific triterpenoid cyclase. The inventive nucleotide sequences and the polypeptide sequences derived therefrom demonstrate a surprisingly minimal sequence identity to known isoprenoid cyclases. The invention also relates to the use of nucleic acids for the regulation of triterpenoid cyclase expression in a host organism, as well as the targeted knockout or repriming of the triterpenoid cyclase gene. As a result of the altered expression of the triterpenoid cyclase, it is possible to modify and enrich the levels of multiple unsaturated fatty acids in the host organism.

SUMMARY OF THE INVENTION

[0008] The present invention is directed to an isolated nucleic acid comprising a nucleic acid sequence encoding a polypeptide or functional variant thereof comprising the amino acid sequence of SEQ ID No. 12.

[0009] In a preferred embodiment, the isolated nucleic acid of the present invention comprises the nucleic acid sequences of SEQ ID No. 11 and SEQ ID No. 13. In another embodiment of the present invention, the isolated nucleic acid comprises at least 8 nucleotides of SEQ ID No. 11. Another embodiment is an isolated nucleic acid of the present invention wherein the nucleic acid is selected from the group comprising DNA, RNA, and double-stranded DNA. In yet another embodiment of the invention, the isolated nucleic acid comprises one or more non-coding sequences.

[0010] In one aspect of the invention, the isolated nucleic acid is antisense. Another aspect relates to a vector comprising the isolated nucleic acid of the present invention, preferably the vector is an expression vector. In addition, the invention is also directed to isolated host cells comprising said vector. Preferably, the host cells are protozoan, in particular, ciliate.

[0011] Another embodiment is a method of producing the isolated nucleic acid of the present invention comprising the step of chemically synthesizing said nucleic acid. An additional embodiment is a method of producing the isolated nucleic acid comprising the step of isolating said nucleic acid from a gene library by screening said library with a probe.

[0012] The present invention also relates to an isolated polypeptide or functional variant thereof comprising the amino acid sequence of SEQ ID No. 12. In particular, the invention relates to an isolated polypeptide comprising at least 6 amino acids of SEQ ID No. 12.

[0013] Also within the scope of the present invention is a method of producing a polypeptide comprising culturing a host cell under conditions sufficient for the production of said polypeptide and recovering said polypeptide from the culture. The host cell may be a protozoa, preferably a ciliate.

[0014] One aspect of the present invention is directed to an antibody capable of binding the polypeptide of SEQ ID No. 12. Another aspect of the present invention relates to a method of producing said antibody of comprising the steps of immunizing a mammal with a polypeptide and isolating said antibodies.

[0015] In one embodiment of the present invention, the isolated nucleic acid is used to identify polypeptide variants comprising the steps of screening a gene library with said nucleic acid and isolating said variant.

[0016] Also within the scope of the present invention is a method of enriching the saturated fatty acid content, in particular the squalene content, in a host cell comprising the step of inactivating the inventive nucleic acid. The nucleic acid may be inactivated by an antisense nucleic acid, by a deletion or insertion of a nucleic acid sequence, or mutation of said nucleic acid sequence. In particular, the inventive nucleic acid may be replaced with one or more selectable markers.

[0017] In another embodiment of the present invention, the isolated nucleic acid is used to produce cyclic triterpenoids, preferably pentacyclic triterpenoids, and most preferred tetrahymanol.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1. Results of a BLASTP database comparison of the protein sequence according to SEQ ID No. 12 with protein databases.

[0019]FIG. 2A. Alignment of the protein sequence according to SEQ ID No. 12 with known pentacyclic triterpenoid cyclases, lanosterol synthesis isolated from Alicyclobacillus acidoterrestris.

[0020]FIG. 2B. Alignment of the protein sequence according to SEQ ID No. 12 with known pentacyclic triterpenoid cyclases, squalene-hopene cyclase isolated from Alicyclobacillus acidocaldarius.

[0021]FIG. 3. Multiple alignment of the polypeptide sequence according to SEQ ID No. 12 from Tetrahymena with known pentacyclic triterpenoid cyclases.

[0022]FIG. 4. Schematic diagram of the gene structure of triterpenoid cyclase from Tetrahymena according to SEQ ID No. 11 and SEQ ID No. 9.

[0023]FIG. 5. Schematic diagram of the triterpenoid knockout construct. A neo-cassette plasmid was inserted into the genomic sequence of Tetrahymena to produce the genetic knockout. The construct contains a neomycin resistance gene regulated by the Tetrahymena histone H4 promoter and the 3′ flanked sequence of the BTU2 (β-tubulin 2) gene. The neo-cassette plasmid was digested with EcoRV and Sma I. The resulting 1.4 kb fragment was then ligated into the EcoRV-digested plasmid pgTHC producing the plasmid pgTHC::neo.

[0024]FIG. 6. Schematic diagram of the pBTHC triterpenoid expression construct. The plasmid (pBICH3-Nsi), which contains the non-coding, regulatory sequences of the Tetrahymena thermophila BTU1 (β-tubulin 1) gene with a Nsi I restriction site at the start codon, was used to generate the tetrahymanol cyclase expression construct, pBTHC. The restriction sites, Nsi I and BamHI, were added by PCR to the 5′ and 3′ ends, respectively, of the coding sequence for Tetrahymena tetrahymanol cyclase. The PCR-modified tetrahymanol cyclase and the plasmid pBICH3-Nsi were digested with the restriction enzymes, Nsi I and BamHI, and purified by an agarose gel. The digested tetrahymanol cyclase fragment was then ligated into the plasmid pBICH3-Nsi and the resulting expression vector, pBTHC, contained the complete coding sequence for triterpenoid cyclase in the correct reading frame and the regulatory sequences of the BTU1 gene.

[0025]FIG. 7. Gamma-linolenic acid (GLA) in % of biodry mass of transformants compared with wild type Tetrahymena. The GLA content of the Tetrahymena triterpenoid cyclase knockout transformants was compared to Tetrahymena wild strain (B2086).

[0026]FIG. 8. Chemical structure of Tetrahymanol.

DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention relates to nucleic acids isolated from Tetrahymena which code for a ciliate-specific triterpenoid cyclase. The inventive nucleotide sequences and the polypeptide sequences derived therefrom demonstrate a surprisingly low sequence identity to known isoprenoid cyclases. Another aspect of the invention is the genomic nucleotide sequence of the triterpenoid cyclase, which in addition to the coding sequence, contains non-coding nucleotide sequences, such as introns, promoters, and flanking sequences. The invention also relates to the use of nucleic acids for regulating expression, targeted knockout, or repriming of this gene. By regulating the expression of the triterpenoid cyclase, it is possible to modify the levels of multiple unsaturated fatty PUFAs in an organism. Moreover, as a result of the targeted knockout of triterpenoid cyclase, an enrichment of squalene, an intermediate in the synthesis of various triterpenoids, can be achieved. Squalene serves as a synthetic module for terpenes. Partially modified squalene (e.g., in hydrogenated form) is used in dermatology products and cosmetics, as well as in various derivatives found in skin and hair care products. In a further embodiment, a targeted overexpression of the inventive nucleic acids may result in the production of cyclic triterpenoids such as pentacyclic triterpenoids (e.g., tetrahymanol or hopane), and tetracyclic triterpenoids (e.g., lanosterol or cycloartenol). Cyclic triterpenoids are used in the synthesis of steroid hormones and saponins. These compounds display good skin penetration and diffusion properties, and therefore, they are also used in cosmetics and dermatology products.

[0028] The inventive nucleic acids can be isolated from ciliates, preferably Tetrahymena, and most preferred from Tetrahymena thermophila.

[0029] One aspect of the present invention is to provide a nucleic acid isolated from Tetrahymena, which codes for a polypeptide with the activity of a triterpenoid cyclase. Another aspect of the invention is the regulation of gene expression or genetic knockout (adequate inhibition) of the triterpenoid cyclase in a host organism, preferably in Tetrahymena, in order to increase the level of PUFAs produced in the organism. In particular, a further aspect is to enrich the levels of gamma-linolenic acid (GLA) by means of the host's own production of PUFA for restoration of membrane stability.

[0030] A further embodiment of the present invention is the nucleic acids according to SEQ ID No. 11 and SEQ ID No. 13, which code for a triterpenoid cyclase with the amino acid sequence according to SEQ ID No. 12 or a functional variant thereof, and fragments thereof with at least 8 nucleotides, preferably with at least 15 or 20 nucleotides, in particular, with at least 100 nucleotides, and most preferred, with at least 300 nucleotides (hereinafter called “inventive nucleic acid(s)”). The nucleic acid according to SEQ ID No. 11 represents the protein-coding (or cDNA) sequence. The nucleic acid, according to SEQ ID No. 13, represents a genomic sequence of the triterpenoid cyclase, which in addition to the coding sequence, also contains non-coding nucleic acid sequences such as introns, promoters, and flanking sequences (such as UTR) (FIG. 4).

[0031] The complete nucleic acid sequence according to SEQ ID No. 11 codes for a protein with 655 amino acids and a theoretical molecular mass of 76.02 kDa. Sequence analysis, as provided in the present invention, confirms that the nucleic acid codes for the pentacyclic triterpenoid cyclase isolated from Tetrahymena. A homology comparison enabled the identification of the protein sequence as a triterpenoid cyclase according to SEQ ID No. 12, which is derived from the nucleic acid sequence (SEQ ID No. 11). A BLASTP search (Altschul et al. (1997) NUCLEIC ACIDS RES. 25:3389-3402) was used for the homology comparison. Isoprenoid cyclases (such as squalene-hopene cyclase, and lanosterol and cycloartenol synthases) were identified as homologous proteins from the database (FIG. 1). The known triterpenoid cyclases have a maximum identity of 28% as compared to the inventive polypeptide sequence (FIG. 2). A multiple alignment of various known isoprenoid cyclases and the inventive polypeptide sequence is shown in FIG. 3. Homologies are observed in the conserved domains. One such domain is the QW-motif (K/R X₂₋₃ F/Y/W L X₃ Q X₂₋₅ G X W; Poralla et al. (1994) TRENDS BIOCHEM. SCI. 19:157-158; Poralla (1994) BIOORG. MED. CHEM. LETT. 4:285-290), which occurs seven to eight times in squalene-hopene cyclases, and seven times in oxidosqualene cyclases. The inventive polypeptide sequence has seven such QW-motifs, which are distinctly less conserved as compared to other known triterpenoid cyclases. Another conserved motif is the aspartate-rich motif (D V/L D D T A; Perzl et al. (1997) MICROBIOLOGY 143:1235-1242), which is less conserved in the inventive polypeptide sequence in the homologous position (D T D D T G). Similar aspartate-rich motifs were found in other enzymes of the isoprenoid biosynthesis pathway (ASHBY ET AL. (1990) in: MOLECULAR BIOLOGY OF ATHEROSCLEROSIS, 27-34. Ed. A D Attie, Amsterdam, Elsevier). While the inventive polypeptide sequence has been identified as triterpenoid cyclase, it differs considerably from other cyclases. The overall identity of the inventive polypeptide sequence as compared to known cyclases is surprisingly small.

[0032] In a preferred embodiment, the inventive nucleic acid is a DNA or RNA molecule, preferably a double-stranded DNA molecule, or a functional variant, of the nucleic acid sequence according to SEQ ID No. 11, or the genomic nucleic acid sequence according to SEQ ID No. 13.

[0033] According to the present invention, the term “functional variant” is defined as a nucleic acid which is functionally related to the triterpenoid cyclase isolated from Tetrahymena, such as other pentacyclic triterpenoid cyclases, or allelic or degenerative variants.

[0034] In a narrower sense, according to the present invention, the tern “variant” is defined as nucleic acids, which have a sequence identity of approximately 60%, preferably of approximately 75%, in particular, of approximately 90%, and most preferred, of approximately 95%. In this case, the degree of hybridization must also be taken into consideration.

[0035] The invention also comprises functional variants of the nucleic acid, which include nucleotide changes that do not alter the protein sequence. Due to the unusual codon use by ciliates (Wuitschick & Karrer (1999) J. EUKARYOT. MICROBIOL. 46(3):239-247), the described DNA sequence must be modified for expression in other systems. For example, codons TAA and TAG, which code for glutamine in ciliates and are stop codons in most other systems, are replaced with the codons CAA and CAG for expression in other organisms. In addition, by modifying the sequence to the respective codon preference (or codon usage) of various organisms, protein expression can be optimized in these organisms. Modification of nucleic acid sequences can be accomplished using methods well known to one skilled in the art. Alternatively, the sequence can be generated by chemically synthesizing oligonucleotides. The specific base changes in the nucleic acid sequence can be determined utilizing known codon usage tables of the preferred expression systems (i.e., Codon usage tabulated from the gene library: http://www.dna.affrc.gojp/˜nakamura/CUTG.html). The present invention also comprises variants of nucleic acids.

[0036] The variants or fragments of the inventive nucleic acids can be used as probes to identify additional functional variants, or as antisense nucleic acids. For example, a nucleic acid of at least approximately 8 nucleotides is suitable as an antisense nucleic acid; a nucleic acid of at least approximately 15 nucleotides as primer for PCR; a nucleic acid of at least approximately 20 nucleotides is suitable for identifying other variants; and a nucleic acid of at least approximately 100 nucleotides is may be used as a probe.

[0037] In a preferred embodiment, the protein-coding sequence of the inventive nucleic acid is deleted or replaced with a selectable gene, such as a gene for antibiotic resistance. Using this approach, the native gene can be “knocked out” in a host organism (gene knockout) by homologous recombination. By replacing or deleting the triterpenoid cyclase gene, the synthesis of cyclic triterpenoids is inhibited resulting in a modification of the fatty acid composition in the host organism. In another aspect of the present invention, the inventive nucleic acid sequence is altered by a deletion, insertion, or point mutation leading to either a reduced or an increased activity of triterpenoid cyclase.

[0038] In another embodiment, the triterpenoid cyclase isolated from Tetrahymena is expressed in another host cell or organism. To accomplish expression in another host, the inventive nucleic acid is ligated into a vector, preferably in an expression vector.

[0039] The expression vectors can be either prokaryotic or eukaryotic expression vectors. For prokaryotic expression, the T7 expression vector, pGM 10, (Martin, 1996) can be expressed in E. coli cells. This vector contains an N-terminal “histidine tag” sequence (Met-Ala-His₆) which can be used for protein purification by Ni2+-NTA affinity chromatography. The eukaryotic expression vectors, p426Met25 and p426GAL1 (Mumberg et al. (1994) NUCL. ACIDS RES., 22:5767-68) are suitable for the expression in Saccharomyces cerevisiae. In insect cells, Baculovirus vectors such as EP-BI-0127839 or EP-B1-0549721 may be used for protein expression, and for expression in mammalian cells, SV40 vectors may be utilized. For detailed information concerning suitable vectors, refer to SAMBROOK ET AL. (1989) MOLECULAR CLONING: A LABORATORY MANUAL, Cold Spring Harbor Laboratory, Cold Spring, N.Y.; Goeddel, ed. (1990) METHODS IN ENZYMOLOGY 185 Academic Press; and PERBAL (1988) A PRACTICAL GUIDE TO MOLECULAR CLONING, John Wiley and Sons, Inc. The recombinant proteins or fragments thereof can be isolated by methods of protein purification that are well known to one skilled in the art (e.g., AUSUBEL ET AL. (1995), CURRENT PROTOCOLS IN MOLECULAR BIOLOGY, Green Publishing Associates, New York).

[0040] The expression vectors preferably contain sequence elements which influence expression, such as promoters, enhancer elements, and “upstream” activating sequences. Inducible and constitutive promoters, as well as tissue-specific promoters, are suitable for expression of the inventive nucleic acids. For example, the cauliflower mosaic virus (CaMV) 35S promoter (Restrepo et al. (1990) PLANT CELL 2:987-98) or promoters which are activated during seed development, are suitable for the expression in plant cells.

[0041] In a preferred embodiment of the present invention, the vectors used for expression of the inventive nucleic acids are shuttle vectors (Wolk et al. (1984) PROC. NATL. ACAD. SCI. USA, 81:1561-1565; and Bustos et al. (1991) J. BACTERIOL. 174:7525-7533).

[0042] Generally, the expression vectors also contain regulatory sequences which are compatible with the host cell, such as the trp promoter for the expression in E. coli (refer to EP-B I-0154133), the ADR2 promoter for the expression in yeast (Russel et al. (1983), J. BIOL. CHEM. 258:2674-82), the Baculovirus polyhedrin promoter for the expression in insect cells (refer to EP-B1-0127839), or the early SV40 promoter or LTR promoters of MMTV (Mouse Mammary Tumor Virus; Lee et al. (1981) NATURE, 294:228-32) for mammalian expression.

[0043] Vectors, which contain the inventive nucleic acid sequence, can be transferred to cells by infection, transfection, electroporation, particle bombardment, and other methods known to those skilled in the art. According to the present invention, transformation is generally defined as the introduction of nucleic acids into a host cell (Sambrook et al. 1989; Potrykus (1991) ANNU. REV. PLANT PHYSIOL. PLANT MOL. BIOL. 42:205-225; Christou (1993) CURR. OP. BIOTECH. 4:135-141).

[0044] In another aspect, the expression vector contains the inventive nucleic acids in functional combination with promoters or other regulatory elements, or in combination with another gene. Preferably the additional gene is a selection marker, such as a gene for antibiotic resistance. In a preferred embodiment, the regulatory elements are nucleic acid sequences which are functionally active in ciliates, and in particular, active in Tetrahymena.

[0045] In another embodiment of the present invention, the inventive nucleic acid is expressed in Tetrahymena under the regulation of a strong promoter, such as the Tetrahymena tubulin promoter (Gaertig et al., (1999) NATURE BIOTECH. 17: 462-465). Preferably, the transformation of Tetrahymena may be achieved according to the methods described by Gaertig et al. (1999); Gaertig & Gorovsky (1992) PROC. NATL. ACAD. Sci. USA 89:9196-9200. In another aspect, the regulatory elements for expression may be the promoters for α- or β-tubulin isolated from Tetrahymena thermophila. The transformed Tetrahymena may be identified using a selection media, such as a media that contains an antibiotic.

[0046] Overexpression of the inventive nucleic acids may result in the production of cyclic triterpenoids, preferably pentacyclic triterpenoids, and most preferred tetrahymanol.

[0047] The inventive nucleic acids can be chemically synthesized based on the sequences disclosed in SEQ ID No. 11 and 13, or based on the peptide sequence disclosed in SEQ ID No. 12 according to the phosphotriester method (Uhlman & Peyman (1990) CHEMICAL REVIEWS, 90:543, No. 4). The inventive nucleic acids may also be isolated from an appropriate cDNA or genomic library generated from an organism possessing isoprenoid cyclase activity (Sambrook, et al., 1989). Single-stranded DNA fragments derived from the nucleic acid sequences according to SEQ ID No. 11 or 13 with a length of approximately 100-1000 nucleotides, preferably with a length of approximately 200-500 nucleotides, and most preferred, with a length of approximately 300-400 nucleotides may be suitable as probes to screen a cDNA or genomic library.

[0048] Another embodiment of the present invention is a polypeptide with an amino acid sequence according to SEQ ID No. 12, or a functional variant thereof. Another aspect is amino acid fragments according to SEQ ID No. 12 with at least six amino acids, preferably with at least 12 amino acids, in particular, with at least 65 amino acids, and, most preferred, with at least 150 amino acids (hereinafter called “inventive polypeptide”). In addition, polypeptides with a length of approximately 6-12 amino acids, preferably approximately 8 amino acids, may contain an epitope. The epitope may be coupled with a carrier and then may be used for the production of polyclonal or monoclonal antibodies (see e.g., U.S. Pat. No. 4,656,435). Polypeptides with a length of at least approximately 65 amino acids may also be used directly, without a carrier, to produce polyclonal or monoclonal antibodies.

[0049] Within the meaning of the present invention, the term “functional variant” is defined as a polypeptide which is functionally associated with the inventive peptide, i.e., it exhibits triterpenoid cyclase activity.

[0050] Also within the meaning of the present invention, the term “variant” includes polypeptides which have sequence homology. In particular, variant includes polypeptides with a sequence identity of approximately 70%, preferably approximately 80%, in particular, approximately 90%, and most preferred, approximately 95% compared to the protein with the amino acid sequence according to SEQ ID No. 12.

[0051] In another aspect, the term variant includes deletions of the polypeptide in the range of approximately 1-60 amino acids, preferably approximately 1-30 amino acids, in particular, approximately 1-15 amino acids, and most preferred, approximately 1-5 amino acids. For example, methionine, the first amino acid of a protein, may be deleted without appreciably altering the function of the polypeptide.

[0052] Another embodiment of the present invention includes fusion proteins, which contain the above-described inventive polypeptides. The fusion proteins may possess triterpenoid cyclase activity, or may gain the activity after the removing a portion of the fusion moiety. These fusion proteins contain, in particular, non-ciliated sequences of approximately 1-200 amino acids, preferably approximately 1-150 amino acids, in particular, approximately 1-100 amino acids, and most preferred, approximately 1-50 amino acids. Examples of non-ciliated peptide sequences include prokaryotic peptide sequences such as galactoidase or a histidine tag (i.e., Met-Ala-His₆ tag). The fusion protein containing a histidine tag is particularly advantageous for purifying the expressed protein by affinity chromatography using metal ion-containing columns such as an Ni2+ NTA column (NTA: chelating nitrilotriacetic acid).

[0053] In a further aspect of the present invention includes variants of the inventive polypeptide which serve as epitopes that can be specifically identified by antibodies.

[0054] The inventive polypeptide can be produced, for example, by expressing the inventive nucleic acid in a suitable expression system according to methods which are generally known to a person skilled in the art. Strains of E. coli (DHS, HB110 or BL21), yeast (Saccharomyces cerevisiae), insect cell lines (Lepidopteran species: Spodoptera frugiperda), or animal cells (COS, Vero, 293, and HeLa) are commercially available and suitable as host cells.

[0055] In another embodiment, peptide variants of the polypeptide can be synthesized by classical peptide synthesis methods (i.e., Merrifield Technique). These peptides can be used to produce antisera that can then be utilized to screen gene expression libraries as a means to identify additional functional variants of the inventive polypeptide.

[0056] Another aspect of the present invention relates to a method for producing an inventive polypeptide by expressing an inventive nucleic acid in a suitable host cell, and if appropriate, isolating the inventive polypeptide.

[0057] The present invention also relates to antibodies which specifically react with the inventive polypeptide, in particular where variants of the polypeptide are either immunogenic or are rendered immunogenic by coupling a suitable carrier, such as bovine serum albumin, to the variant. The antibodies of the present invention may be either polyclonal or monoclonal.

[0058] The method of producing antibodies is another aspect of the present invention. Antibodies can be generated according to methods generally known in the art. For example, a mammal, such as a rabbit, may be immunized with the inventive polypeptide or variant thereof, and if appropriate, in the presence of an adjuvant (e.g., Freund's adjuvant or aluminum hydroxide gels) (Diamond et al. (1981) N. ENGL. J. MED., 304:1344-49). The polyclonal antibodies produced in the animal as a result of the immunological response, can easily be isolated from blood using methods generally known in the art. For example, antibodies may be purified by column chromatography. A preferred method of antibody purification is affinity chromatography, for example, the HiTrap™ NHS-activated columns (Pharmacia, Piscataway, N.J.). Monoclonal antibodies can be produced according to the methods described by Winter & Milstein (Winter & Milstein, (1991) NATURE, 349:293-99).

[0059] In a preferred embodiment, the inventive nucleic acids are used to produce a genetic knockout of triterpenoid cyclase in a host organism, preferably Tetrahymena. As a result of this gene knockout, the levels of PUFA, in particular, GLA, are increased in the host organism. A gene knockout in Tetrahymena can be accomplished by homologous recombination wherein a nucleic acid according to SEQ ID No. 11 or 13 is modified by replacing the protein-coding sequence with a selectable gene (e.g., an antibiotic resistant gene) (Gaertig et al. (1994) NUCL. ACIDS RES. 22:5391-5398; Kahn et al. (1993) PROC. NATL. ACAD. SCI. USA 90:9295-9299). In addition to gene knockout technology (Galli-Taliadoros (1995) J. IMMUNOL. METHODS 181:1-15), an antisense strategy (Atkins et al. (1994) BIOL. CHEM. HOPPE SEYLER 375:721-729) or the antisense ribosome method (Sweeney et al. (1996) PROC. NATL. ACAD. Sci. USA 93:8518-8523) may be utilized to reduce activity of triterpenoid cyclase.

[0060] The inventive nucleic acids of the present invention code for a ciliate-specific triterpenoid cyclase isolated from Tetrahymena. These nucleic acids can be used to generate transgenic organisms, preferably Tetrahymena, which contain an increased level of unsaturated fatty acids. In a preferred embodiment of the present invention, the inventive nucleic acids may be utilized in the commercial production of PUFAs, in particular, GLA. In another embodiment, the GLA content of the transgenic organism (i.e., a transgenic Tetrahymena) may be increased by the combination of a genetic knockout (or reduction) of tetrahymanol cyclase activity and a functional overexpression of fatty acid desaturase.

[0061] In a preferred embodiment, a host organism, preferably Tetrahymena, is transformed with the inventive nucleic acid or the above-described structures (Gaertig et al. (1999); Gaertig & Gorovsky (1992); Gaertig et al. (1994); Kahn et al. (1993) PROC. NATL. ACAD. Sci. USA 90:9295-9299).

[0062] The transformed Tetrahymena may be grown and enriched in a selective media, and then lipid(s) may be isolated from these cells according to standard methods (e.g., Dahmer et al., (1989) J. AM. OIL CHEM. SOC. 66:543). The methyl esters of fatty acids can be analyzed by gas chromatography.

[0063] The inventive nucleic acids or variants thereof can also be used to identify related genes from other organisms, in particular, from other protozoa or protista, preferably ciliates (systematized according to Cavalier Smith (1995) ARCH. PROTISTENK. 145:189-207). The inventive nucleic acid or variants thereof can be used as a labeled probe for isolating homologous genes. By hybridizing the labeled probe with isolated nucleic acids or other organisms, homologous nucleic acid sequences may be detected and isolated. The nucleic acid probe can be labeled in a manner known to the person skilled in the art (Ausubel et al., 1995; Sambrook et al., 1989). For example, radioactive nucleotides or nucleotides linked to detectable molecules, such as fluorophores, digoxigenin, biotin, magnetic molecules or enzymes, may be used to label the nucleic acid probe. Homologous DNA sequences may be identified by hybridization of the labeled probe. Genomic or cDNA libraries may be used to screen for homologous sequences. In addition, Southern and Northern blots may also be used to identify homologous sequences. Alternatively, homologous DNA may be hybridized with a labeled probe, and isolated by selective retention of the labeled probe (e.g., a magnet).

[0064] Homologous genes can also be isolated and cloned by means of cross-hybridization, using methods which are known to a person skilled in the art, as described, for example, in Ausubel et al. (1995), or Sambrook et al. (1989).

[0065] Oligonucleotides can be generated based on an isolated DNA sequence which represents the protein coding sequence and these oligonucleotides can then be used to identify additional homologous nucleic acid sequences by polymerase chain reaction (PCR).

[0066] Detection with specific antibodies against the protein or variants thereof (such as peptide antibodies) coded by the nucleic acid sequence of the present invention, provides another option for isolating homologous proteins.

[0067] A plurality of well-established methods such as the methods described in Sambrook et al. (1989) are well known in the art for isolating genomic DNA and mRNA, as well as for producing genomic and cDNA libraries.

EXAMPLES

[0068] The following examples serve to illustrate the invention, without limiting the invention to these examples.

Example 1 Organisms and Culture Conditions

[0069]Tetrahymena thermophila (Strains B 1868 VII, B2086 μl, B*VI, CU522 were provided by Dr. J. Gaertig, University of Georgia, Athens, Ga., USA) were grown in modified SPP medium (2% proteosepeptone, 0.1% yeast extract, 0.2% glucose, and 0.003% Fe-EDTA (Gaertig et al. (1994) PROC. NATL. ACAD. Sci. USA 91:4549-4553)); skim milk medium (2% skim milk powder, 0.5% yeast extract, 1% glucose, and 0.003% Fe-EDTA); or MYG medium (2% skim milk powder, 0.1% yeast extract, 0.2% glucose, and 0.003% Fe-EDTA) with the addition of an antibiotic solution (100 U/ml penicillin, 100 μg/ml streptomycin, and 0.25 μg/ml amphotericin B) (SPPA medium) at 30° C. in a 50 ml volume in a 250 ml Erlenmeyer flask, with shaking (150 rpm).

[0070] Plasmids and phages were reproduced and selected in E. coli XL1-Blue MRF′, TOP10F′, or JM109 cells. The bacteria were grown under standard conditions in LB or NZY medium with antibiotics in standard concentrations (Sambrook et al., 1989).

Example 2 Preparation of a Tetrahymena thermophila cDNA Library

[0071] Total RNA was isolated from Tetrahymena thermophila according to the guanidine thiocyanate/phenol/chloroform method (Chomzynski & Sacchi (1987) ANAL. BIOCHEM. 161:156-159). From total RNA, mRNA was extracted using Oligotex™ mRNA Purification System (Qiagen, Germany). The synthesis of cDNA was performed according to the Stratagene ZAP Express® cDNA Synthesis and Cloning Kit (Stratagene, LaJolla, Calif.). Following ligation of EcoRI adapters and digestion with Xho I, the cDNA was separated on an agarose gel according to size (S: 500-1500 bp, B: greater than 1500 bp). The cDNA was purified from the gel (QIAquick™ Gel Extraction Kit; Qiagen) and ligated into the ZAP express vector which had been cut with EcoRI and Xho I. The ligated cDNA was then packaged into phage in vitro (Gigapack® III Gold; Stratagene). The phage were reproduced in E. coli XL1-Blue MRF′. The S-cDNA library contained approximately 5×10⁵ clones with an average insertion size of 1.1 kb, and the B-cDNA library contained approximately 6×10⁴ clones with an average insertion size of 2 kb.

Example 3 Preparing a Tetrahymena thermophila Genomic DNA Library

[0072] Genomic DNA was isolated from Tetrahymena by the Urea Method (Gaertig et al., 1994). The genomic DNA was digested with EcoRI and the cut DNA was then ligated into an EcoRI-digested Lambda vector (ZapExpress, Stratagene). The library was generated using a method similar to the method described for cDNA library preparation in Example 2.

Example 4 RT-PCR with Triterpenoid Cyclase-Specific Primers

[0073] Sequence comparisons of known pentacyclic triterpenoid cyclases were used to identify conserved regions. PCR primers were designed for the highly conserved regions, GSWF/YGR/SWGV/I and DGGWGE, taking into consideration the ciliate codon or Tetrahymena codon usage (Wuitschick & Karrer (1999) J. EUKARYOT. MICROBIOL. 1999 46(3):239-47; CUTG, (Codon Usage Tabulated from gene library): http://www.dna.affrc.go.jp/˜nakamura/CUTG.html).

[0074] The following primers were used for the PCR reactions: 5′-GGTTCNTGGTAYGGTAGATGGG-3′; SEQ ID No. 1 and: 5′-TTCACCCCAACCACCATC-3′. SEQ ID No. 2

[0075] Isolated mRNA (100 ng) was used for the initial strand synthesis catalyzed by the enzyme, AMV Reverse Transcriptase (Boehringer Mannheim, Indianapolis, Ind.). According to the manufacturer's protocol, the final reaction volume was 20 μl and contained: 50 mM Tris-HCl (pH 8.5), 8 mM MgCl₂, 30 mM KCl, 1 mM DTT, 1 mM dNTPs, 2 U AMV Reverse Transcriptase, and 2 pmol Oligo-dT anchor primer, SEQ ID No. 3: 5′-GACCACGCGTATCGATGTCGACT₁₆V-3′.

[0076] The reaction was incubated for 1 hour at 55° C., followed by a 10-minute incubation at 65° C. An aliquot ({fraction (1/10)} volume) of the initial strand reaction was used for the PCR. The PCR reaction volume was 25 μl: 1% HotStarTaq™ PCR Buffer (Qiagen, Germany), 10 pmol of each gene-specific primer (SEQ ID No. 1 and SEQ ID No. 2), 200 μM dNTPs, 1.5 mM MgCl₂, and 1 U HotStarTaq™ DNA Polymerase (Qiagen). The PCR reaction was performed under the following conditions: an initial denaturization at 95° C. for 15 minutes, followed by 35 cycles at 94° C. for 30 seconds, 45° C. for 30 seconds, 72° C. for 1 minute, and a final incubation at 72° C. for 10 minutes. The PCR fragments were ligated into the TA Cloning® vector, pCR 2.1, using the TA Cloning® kit (Invitrogen, San Diego, Calif.), and then transformed into E. coli TOP10F′ (Invitrogen). Plasmid DNA was isolated from positive clones (QIAprep® Spin kit, Qiagen) and sequenced.

Example 5 Isolation of the Triterpenoid Cyclase cDNA

[0077] Based on a preliminary sequence, new oligonucleotide primers were designed for PCR, SEQ ID No. 4: 5′-CTGTTGGAGCTGTTGTACCAGG-3′ and SEQ ID No. 5: 5′-CGTAATTGACTCTTGCTAAACCTGG-3′.

[0078] The triterpenoid cyclase cDNA was generated by PCR using these primers in combination with vector-specific primers (T3 and T7). An aliquot of the S-cDNA library (2 μl; 10⁵ PFU/μl) was used for the PCR reaction (see Example 2). PCR was performed according to the following protocol: DNA denaturization for 15 minutes at 95° C.; followed by 35 cycles at 94° C. for 20 seconds, 57° C. for 20 seconds, 72° C. for 2 minutes; and a final incubation at 72° C. for 10 minutes. The PCR products then were cloned (see Example 2) and sequenced.

[0079] A new primer was designed based on this sequence information. The primer was located at the 5′-end of the cDNA sequence, SEQ ID No. 6: 5′-GCTAAAACTCTTTCATACATGAAGAAG-3′.

[0080] Using this primer in combination with a vector-specific primer, the complete cDNA was amplified by PCR (see above for PCR conditions) from the cDNA library. The PCR product was sequenced and the corresponding cDNA sequence is listed as SEQ ID No. 11. The protein sequence can be derived from the cDNA sequence taking into consideration the specific codon usage.

Example 6 Isolation of the Genomic Sequence of Triterpenoid Cyclase

[0081] By screening a genomic library with a digoxigenin-labeled PCR-generated triterpenoid cyclase, a clone was isolated with a DNA insert of approximately 5000 bp. The clone was isolated from the phage by in vitro excision producing the plasmid pgTHC. The DNA insert was sequenced (SEQ ID No. 13) by primer walking. Comparing the cDNA sequence (SEQ ID No. 11) with this sequence, the introns and flanking sequences were identified (FIG. 4).

Example 7 Preparation of Triterpenoid Cyclase Knockout Constructs

[0082] A neo-cassette plasmid, p4T2-1ΔH3, (Gaertig et al., 1994) was inserted into the genomic sequence of Tetrahymena to produce the genetic knockout. The construct contains a neomycin resistance gene regulated by the Tetrahymena histone H4 promoter and the 3′ flanked sequence of the BTU2 (β-tubulin 2) gene. In Tetrahymena, this plasmid provides resistance to paromomycin. The plasmid p4T2-1ΔH3 was digested with EcoRV and Sma I. The resulting 1.4 kb fragment was then ligated into the EcoRV-digested plasmid pgTHC producing the plasmid pgTHC::neo. With a successful transformation, the gene for the triterpenoid cyclase was replaced by this construct by homologous recombination, and as a result, the cells were resistant to paromomycin.

Example 8 Preparation of the Expression Construct, pBTHC

[0083] The vector pBICH3 (Gaertig et al., 1999) contains the coding sequence for the Ichthyophthirius I antigen (G1) preprotein flanked by the non-coding, regulatory sequences of the Tetrahymena thermophila BTU1 (β-tubulin 1) gene. A modified plasmid (pBICH3-Nsi) with a Nsi I restriction site at the start codon (provided by J. Gaertig, University of Georgia, Athens, Ga., USA) was used to generate the tetrahymanol cyclase expression construct, pBTHC. The restriction sites, Nsi I and BamHI, were added by PCR to the 5′ and 3′ ends, respectively, of the coding sequence for Tetrahymena tetrahymanol cyclase. Isolated plasmid containing the complete cDNA sequence for tetrahymanol cyclase (pTHC) was used as the template for PCR. The primers, SEQ ID No. 7 5;-CTCTTTCATACATGCATAAGATACTCATAGGC-3′ and: SEQ ID No. 8 5′-GGCTTGGATCCTCAAATATTTTATTTTTATACAGG-3′,:

[0084] were used to generate the PCR products, which contained the complete coding sequence of tetrahymanol cyclase flanked by Nsi I and BamHI restriction sites. The PCR products and the plasmid pBICH3-Nsi were digested with the restriction enzymes, Nsi I and BamHI, and purified by an agarose gel. The resulting expression vector, pBTHC, contained the complete coding sequence for triterpenoid cyclase in the correct reading frame and the regulatory sequences of the BTU1 gene (FIG. 6). For the transformation of Tetrahymena, the vectors were linearized by digestion with the restriction enzymes, Xba I and Sal I.

[0085] In a successful transformation, these constructs replaced the BTU1 gene via homologous recombination, and as a result, the cells were resistant to Paclitaxel.

Example 9 Determining the Fatty Acid Spectrum of the Transformants

[0086] The fatty acid spectrum was determined using a gas chromatography system with a flame ionization detector (HP GC 6890; Hewlett-Packard, Wilmington, Del.). An FFAP (Free Fatty Acid Phase) Permbond (Macherey & Nagel GmbH, Düren) was used as the column. The fatty acids were identified by comparing the retention times of fatty acid methyl ester standards. The concentration of fatty acids in the samples was determined on the basis of the known standard concentration. To determine the fatty acid spectrum, isolated transformants in MYG medium (plus 10 μg/ml cholesterol) were grown at 30° C. with shaking (150) rpm for 24-96 hours. An aliquot of the culture (50 ml) was centrifuged at 1500×g for 15 minutes. The supernatant was discarded and the pellet was frozen at −80° C. and subsequently freeze-dried. The lyophilized sample (50 mg) was resuspended in 1 ml of 20% methanolic HCl and 1 ml of methanolic standard solution (1 mg/ml). To release the fatty acids and their transesterification of fatty acid methyl ester, the samples were agitated in a water bath for two hours at 60° C., and then cooled to room temperature. Aqueous, saturated sodium hydrogen carbonate solution (1 ml) was added to neutralize the sample, and the samples were mixed carefully. The fatty acid methyl ester was extracted by the addition of n-Hexane. The sample was thoroughly mixed, and a phase separation was achieved by a 2-minute centrifugation at 4,300 rpm. About ⅔ of the upper, organic phase was removed, and 1 μl of the sample was injected into the GC column, and analyzed. The GLA content of the Tetrahymena triterpenoid cyclase knockout transformants as compared to the Tetrahymena wild strain (B2086) is shown in Table 1. TABLE 1 Time % GLA/BTM % GLA/BTM % Difference % GLA/BTM % Difference (hours) B2086 AX004a AX004a AX081 AX081  6 1.10 1.03 −6.8% 1.08 −1.9% 21 1.24 1.32 +6.5% 1.44 +16.1% 32 1.37 1.57 +14.6% 1.76 +28.5% 54 1.54 1.96 +27.3% 1.98 +28.6%

[0087] GLA content of the Tetrahymena triterpenoid cyclase knockout transformants was compared to Tetrahymena wild strain (B2086). The table specifies the GLA percentile in the biodrymass (% GLA/BTM) and the percentile difference (% difference) of the transformants compared to the wild strain B2086.

Example 10 Macronucleus Transformation of Tetrahymena with the Tetrahymanol Cyclase Expression Construct, pBTHC

[0088]Tetrahymena thermophila cells (5×10⁶; CU522) were used for transformation. The cells were grown in 50 ml SPPA medium at 30° C. in a 250 ml Erlenmeyer flask on a shaker (150 rpm) to a cell density of approximately 3-5×10⁵ cells/ml. The cells were pelleted for 5 minutes by centrifugation (1200×g). The cell pellets were resuspended in 50 ml of 10 mM Tris-HCl (pH 7.5), and then centrifuged as before. This washing step was repeated. The cells were resuspended in 10 mM Tris-HCl (pH 7.5) with antibiotics at a cell density of 3×10⁵ cells/ml. The cells were transferred to a 250 ml Erlenmeyer flask, and incubated for 16-20 hours without shaking at 30° C. (starvation phase). Following the starvation phase, the number of cells was determined. The cells were centrifuged as above, and then resuspended in 10 mM Tris-HCl (pH 7.5) at a concentration of 5×10⁵ cells/ml. One ml of cells was used for the transformation. The transformation was performed by microparticle bombardment (see Example 12). To regenerate, the cells were resuspended in SSPA medium, and incubated in an Erlenmeyer flask at 30° C. without shaking. After 3 hours, Paclitaxel was added to the medium in a final concentration of 20 μM. The cells were transferred in aliquots of 100 μl to 96-well microtiter plates and incubated in a humid, dark box at 30° C. After 2-3 days, the Paclitaxel-resistant clones were identified. Positive clones were hetero-inoculated in fresh medium with 25 μM Paclitaxel. By cultivating the cells with an increased Paclitaxel concentration (up to 80 μM), a complete “phenotypic assortment” was achieved as described by Gaertig & Kapler (1999).

[0089] To analyze the clones, DNA was extracted from approximately 4 ml cultures as described in Gaertig et al.(1994). DNA integrated in the BTU1 (β-tubulin 1) locus was amplified by PCR using BTU1-specific primers SEQ ID No. 9: 5′-AAAAATAAAAAAGTTTGAAAAAAAACCTTC-3′, located approximately 50 bp upstream of the start codon; and SEQ ID No. 10: 5′-GTTTAGCTGACCGATTCAGTTGTTC-3′, 3 bp after the stop codon).

[0090] The PCR products was analyzed, uncut and cut with Hind m, Sac I or Pst I, on a 1% agarose gel. The complete “phenotypic assortment” was verified via RT-PCR with BTU1-specific primers (Gaertig & Kapler, 1999).

Example 11 Micronucleus and Macronucleus Transformation of Tetrahymena with the Knockout Construct, pgTHC::neo

[0091] Tetrahymena strains of varying pairing types (CU428 VII and B2086 μl) were separated in SPPA medium at 30° C. with shaking (150 rpm), and cultivated in an Erlenmeyer flask. With a cell density of 3-5×10⁵ cells/ml, the cell were washed three times with 50 ml of 10 mM Tris-HCl (pH 7.5), and then resuspended in 50 ml of 10 mM Tris-HCl (pH 7.5) diluted with an antibiotic solution. The cells were incubated in an Erlenmeyer flask at 30° C. without shaking. After approximately 4 hours, both cultures were recounted and diluted with 10 mM Tris-HCl (pH 7.5) to 3-5×10⁵ cells and incubated for an additional 16-20 hours at 30° C. Following the starvation phase, the same (absolute) number of cells from each of the two cultures was mixed in a 2-liter Erlenmeyer flask. The cells were incubated at 30° C. (start of conjugation) and after 2 hours, the efficiency of the conjugation was determined. To ensure a successful transformation, approximately 30% of the cells should be in the form of pairs.

[0092] For the micronucleus transformation, at 3, 3.5, 4, and 4.5 hour timepoints following the start of conjugation, 1×10⁷ conjugated cells (5×10⁶ pairs) were centrifuged for 5 minutes at 1200×g. The cell pellet was resuspended in 1 ml of 10 mM Tris-HCl (pH 7.5).

[0093] For transformation of the new macronucleus systems, 11 hours following the start of conjugation, the cells were centrifuged as above and suspended in the Tris-HCl. The transformation was performed by microparticle bombardment (see Example 12). Cholesterol (10 μg/ml) was added to the medium for cultivating the tetrahymanol cyclase knockout mutants.

[0094] The transformed cells were identified by paromomycin resistance selection. During the transformation of the micronucleus, paromomycin (100 μg/ml final concentration) was added 11 hours after the start of the conjugation. The cells were distributed in aliquots of 100 μl onto 96-well microtiter plates and then incubated in a moist box at 30° C. After 2-3 days, the paromomycin resistant clones were identified. Genuine micronucleus transformants could be differentiated by a comparison with the resistance for 6-methylpurin.

[0095] During the transformation of the macronucleus, paromomycin (100 μg/ml final concentration) was added approximately 4 hours following the transformation. The cells were distributed in aliquots of 100 μl onto 96-well microtiter plates and then incubated in a moist box at 30° C. After 2-3 days the resistant clones were identified. Positive clones were hetero-inoculated in fresh medium containing 120 μg/ml paromomycin. By culturing the cells in this high concentration of paromomycin, a complete “phenotypic assortment” (Gaertig & Kapler, 1999) was achieved.

[0096] By crossing micronucleus transformants with a B*VI strain, homozygous knockout mutants were generated (Bruns & Cassidy-Hanley (1999) METHODS IN CELL BIOLOGY 62:229-240).

Example 12 Biolistic Transformation (Microparticle Bombardment)

[0097] The transformation of Tetrahymena thermophila is achieved by the methods described by Bruns & Cassidy-Hanley (1999) METHODS IN CELL BIOLOGY 62:501-512; Gaertig et al. (1999); and Cassidy-Hanley et al.(1997) GENETICS 146:135-147. The use of the Biolistic® PDS-1000/He Particle Delivery System (BIO-RAD) is detailed in the manufacturer's manual.

[0098] For the transformation, gold particles (6 mg; 0.6 μm; BIO-RAD) were loaded with linearized plasmid DNA (10 μg) as described by Sanford et al. (1991) BIOTECHNIQUES 3:3-16; and Bruns & Cassidy-Hanley (1999).

[0099] Preparation of the gold particles. The gold particles were resuspended in 1 ml ethanol and then thoroughly vortexed 3 times for 1-2 minutes. Subsequently, the particles were centrifuged for 1 minute at 10,000×g, and the supernatant was carefully removed with a pipet. The gold particles were then resuspended in 1 ml sterile water and centrifuged as described above. This wash phase was repeated. The particles were then resuspended in 1 ml 50% glycerol and stored in aliquots of 100 μl at −20° C.

[0100] Loading the gold particles with DNA. All preparation was performed at 4° C. The gold particles, DNA vector, 2.5 M CaCl₂, 1 M spermidine, 70% and 100% ethanol were cooled on ice. The linearized DNA vector (10 μl; 1 μg/ml) was added to the gold particles (100 μl) and carefully vortexed for 10 seconds. Initially, 2.5 M CaCl₂ (100 μl) was added to the DNA-gold particles, vortexed for 10 seconds, and then spermidine (40 μl) was added and the sample was carefully vortexed for 10 minutes. Following the addition of 70% ethanol (200 μl), the DNA-gold particles were vortexed for 1 minute and then centrifuged for 1 minute at 10,000×g. The pellets were resuspended in 100% ethanol (20 μl), centrifuged, and then resuspended in 35 μl 100% ethanol.

[0101] Preparation of the macrocarrier. The macrocarrier holder, macrocarrier, and stop screens were placed in 100% ethanol for several hours, and the rupture disks were placed in isopropanol. Subsequently, one macrocarrier was inserted into the macrocarrier and air-dried. The prepared gold particles were then placed carefully in the center of the macrocarrier using a pipet. The macrocarrier was stored in a box with hygroscopic silica gel until the transformation.

[0102] Transformation. Prepared cells (1 ml) were placed in the center of a circular filter which was situated in a Petri dish. The filter was moistened with 10 mM Tris-HCl (pH 7.5), and placed into the lowest insert slot of the transformation chamber of the Biolistic® PDS-100/He Particle Delivery System. Transformation with the prepared gold particles was performed at a pressure of 900 psi (two 450 psi rapture disks) and a vacuum of 27 mmHg in the transformation chamber. The cells were then transferred immediately to an Erlenmeyer flask with 50 ml SPPA medium and incubated at 30° C., without shaking.

[0103] Various modifications and variations of the described methods and systems of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in molecular biology or related fields are intended to be within the scope of the following claims.

[0104] The disclosures of all references and publications cited above are expressly incorporated by reference in their entireties to the same extent as if each were incorporated by reference individually.

1 23 1 22 DNA Artificial Sequence Description of Artificial Sequence Primer 1 ggttcntggt anggtagatg gg 22 2 18 DNA Artificial Sequence Description of Artificial Sequence Primer 2 ttcaccccaa ccaccatc 18 3 39 DNA Artificial Sequence Description of Artificial Sequence Primer 3 gaccacgcgt atcgatgtcg actttttttt ttttttttv 39 4 22 DNA Artificial Sequence Description of Artificial Sequence Primer 4 ctgttggagc tgttgtacca gg 22 5 25 DNA Artificial Sequence Description of Artificial Sequence Primer 5 cgtaattgac tcttgctaaa cctgg 25 6 27 DNA Artificial Sequence Description of Artificial Sequence Primer 6 gctaaaactc tttcatacat gaagaag 27 7 32 DNA Artificial Sequence Description of Artificial Sequence Primer 7 ctctttcata catgcataag atactcatag gc 32 8 35 DNA Artificial Sequence Description of Artificial Sequence Primer 8 ggcttggatc ctcaaatatt ttatttttat acagg 35 9 30 DNA Artificial Sequence Description of Artificial Sequence Primer 9 aaaaataaaa aagtttgaaa aaaaaccttc 30 10 22 DNA Artificial Sequence Description of Artificial Sequence Primer 10 gtttagctga ccgattcagt tc 22 11 2072 DNA Tetrahymena thermophila 11 aaaaaagcta aaactctttc atacatgaag aagatactca taggcttaat tataggtctc 60 tttttattct caagcgttaa tgccagcgtt aatctcactg aagtctaaaa tgccatctct 120 atctagcaag gcattaattg ggcagaagta cacaacaata cttggtacta tcctccttac 180 ttaggcgaaa tgtttatcag tgaatactac ttcgagttac tcgtcttgaa ttggactcat 240 aaatctgctt tcaacgctac atactttaca gaacgtctcc tctagactta attcgaagat 300 ggttcatggg agcaagtcag agaacaaaat cttgaaactg gttagttaga tgctactgtc 360 tttaactact ggtacttaaa gtctattaac aacaatccta aaattgaagc tgctctataa 420 aaggctagaa aatggatagt tgcttagggt ggtattgaag caactcaaac aatgaccaag 480 tttaagttag cagccttcgg ttaatacagt tgggaagatt tatggtatgt cccattgttc 540 atcttcaagt agaatggaat tttcaaatat acctacgtta aggatattgt tgcataatgg 600 gtctatccac atttaactgc cttagcttat ttgcgttact aaagaactgt tttcaatgtt 660 cctgttgctg atttgagaga gctctggatc aattacccta agaacggtat taaaatcagt 720 ccaagagaat actctacact taatcctgat agcgatctct tgatcttaat ggacgaaatc 780 ttcaaactta aacaacctct tggaagtttc ggtgcctaca ctatttcaac cctcttgact 840 ttaatgtcct tcaaagactt ttagtcaaag caccctcatc tataccaaaa cgaaatacaa 900 aaggcttacg aagacggata ctatttcgtt gagtttaact actttaactt tagagaagct 960 tatcacggct ctttggatga tggtagatgg tgggatacca ttcttattag ttgggctatg 1020 cttgaaagtg gctaagataa agaaagaatc ttccctatcg tataaaatat ggtcaaagaa 1080 ggtctttaac ctaaaaaagg tataggttat ggatatgatt tcgaatatgc tcctgacact 1140 gatgacactg gattacttct cgttgttatg agttactaca aagaagcctt ctaaaagtaa 1200 atccctgaaa ctattgaatg gcttttctct atgcaaaatg acgatggtgg ctatccagct 1260 tttgacaaag gtaaaaatga agacaattta ttgttcaagt ttgccttcaa tatggctggt 1320 attgctaact cagctgaaat cttcgatccc tcatgtcctg atattactgg tcacatcatg 1380 gaaggattgg gtgagtttgg atatcaagct aatcatcctt agatttaaaa tatgattaaa 1440 tatcaaagaa agacttagaa caagtgggga tcttggtaag ctagatgggg tgtaaattac 1500 attatggctg ttggagctgt tgtaccaggt ttagcaagag tcaattacga cttaaatgaa 1560 cagtgggtac aaaatagtat aaattatttg cttaataaat aaaataaaga tggtggcttt 1620 ggtgaatgtg tcctttctta taatgatcct gaaaagtgga atggtatagg taaatctact 1680 gtcactcaaa cctcatgggg actattagct cttttagaag tttataatta aaatgaacaa 1740 attaagcatg ctgcagatag agctgcttag tatttattag attaattcaa aagagacgat 1800 aataccttct atgatcactc cacaatagga acaggtcaca gaggattact ctatttatag 1860 tacccctcat atgcacaatc attcccatta gtagctttaa atagatacta aaaaatatct 1920 caaggttaat atcacttctc caaaaatttg tacaatggta atggagaacc tgtataaaaa 1980 taaaatattt gaaaattcaa taaactgtat tttacatttt aaatttattt gtattttttt 2040 aagttatttt ttcataaaat aaaaaaaaaa aa 2072 12 655 PRT Tetrahymena thermophila 12 Met Lys Lys Ile Leu Ile Gly Leu Ile Ile Gly Leu Phe Leu Phe Ser 1 5 10 15 Ser Val Asn Ala Ser Val Asn Leu Thr Glu Val Gln Asn Ala Ile Ser 20 25 30 Ile Gln Gln Gly Ile Asn Trp Ala Glu Val His Asn Asn Thr Trp Tyr 35 40 45 Tyr Pro Pro Tyr Leu Gly Glu Met Phe Ile Ser Glu Tyr Tyr Phe Glu 50 55 60 Leu Leu Val Leu Asn Trp Thr His Lys Ser Ala Phe Asn Ala Thr Tyr 65 70 75 80 Phe Thr Glu Arg Leu Leu Gln Thr Gln Phe Glu Asp Gly Ser Trp Glu 85 90 95 Gln Val Arg Glu Gln Asn Leu Glu Thr Gly Gln Leu Asp Ala Thr Val 100 105 110 Phe Asn Tyr Trp Tyr Leu Lys Ser Ile Asn Asn Asn Pro Lys Ile Glu 115 120 125 Ala Ala Leu Gln Lys Ala Arg Lys Trp Ile Val Ala Gln Gly Gly Ile 130 135 140 Glu Ala Thr Gln Thr Met Thr Lys Phe Lys Leu Ala Ala Phe Gly Gln 145 150 155 160 Tyr Ser Trp Glu Asp Leu Trp Tyr Val Pro Leu Phe Ile Phe Lys Gln 165 170 175 Asn Gly Ile Phe Lys Tyr Thr Tyr Val Lys Asp Ile Val Ala Gln Trp 180 185 190 Val Tyr Pro His Leu Thr Ala Leu Ala Tyr Leu Arg Tyr Gln Arg Thr 195 200 205 Val Phe Asn Val Pro Val Ala Asp Leu Arg Glu Leu Trp Ile Asn Tyr 210 215 220 Pro Lys Asn Gly Ile Lys Ile Ser Pro Arg Glu Tyr Ser Thr Leu Asn 225 230 235 240 Pro Asp Ser Asp Leu Leu Ile Leu Met Asp Glu Ile Phe Lys Leu Lys 245 250 255 Gln Pro Leu Gly Ser Phe Gly Ala Tyr Thr Ile Ser Thr Leu Leu Thr 260 265 270 Leu Met Ser Phe Lys Asp Phe Gln Ser Lys His Pro His Leu Tyr Gln 275 280 285 Asn Glu Ile Gln Lys Ala Tyr Glu Asp Gly Tyr Tyr Phe Val Glu Phe 290 295 300 Asn Tyr Phe Asn Phe Arg Glu Ala Tyr His Gly Ser Leu Asp Asp Gly 305 310 315 320 Arg Trp Trp Asp Thr Ile Leu Ile Ser Trp Ala Met Leu Glu Ser Gly 325 330 335 Gln Asp Lys Glu Arg Ile Phe Pro Ile Val Gln Asn Met Val Lys Glu 340 345 350 Gly Leu Gln Pro Lys Lys Gly Ile Gly Tyr Gly Tyr Asp Phe Glu Tyr 355 360 365 Ala Pro Asp Thr Asp Asp Thr Gly Leu Leu Leu Val Val Met Ser Tyr 370 375 380 Tyr Lys Glu Ala Phe Gln Lys Gln Ile Pro Glu Thr Ile Glu Trp Leu 385 390 395 400 Phe Ser Met Gln Asn Asp Asp Gly Gly Tyr Pro Ala Phe Asp Lys Gly 405 410 415 Lys Asn Glu Asp Asn Leu Leu Phe Lys Phe Ala Phe Asn Met Ala Gly 420 425 430 Ile Ala Asn Ser Ala Glu Ile Phe Asp Pro Ser Cys Pro Asp Ile Thr 435 440 445 Gly His Ile Met Glu Gly Leu Gly Glu Phe Gly Tyr Gln Ala Asn His 450 455 460 Pro Gln Ile Gln Asn Met Ile Lys Tyr Gln Arg Lys Thr Gln Asn Lys 465 470 475 480 Trp Gly Ser Trp Gln Ala Arg Trp Gly Val Asn Tyr Ile Met Ala Val 485 490 495 Gly Ala Val Val Pro Gly Leu Ala Arg Val Asn Tyr Asp Leu Asn Glu 500 505 510 Gln Trp Val Gln Asn Ser Ile Asn Tyr Leu Leu Asn Lys Gln Asn Lys 515 520 525 Asp Gly Gly Phe Gly Glu Cys Val Leu Ser Tyr Asn Asp Pro Glu Lys 530 535 540 Trp Asn Gly Ile Gly Lys Ser Thr Val Thr Gln Thr Ser Trp Gly Leu 545 550 555 560 Leu Ala Leu Leu Glu Val Tyr Asn Gln Asn Glu Gln Ile Lys His Ala 565 570 575 Ala Asp Arg Ala Ala Gln Tyr Leu Leu Asp Gln Phe Lys Arg Asp Asp 580 585 590 Asn Thr Phe Tyr Asp His Ser Thr Ile Gly Thr Gly His Arg Gly Leu 595 600 605 Leu Tyr Leu Gln Tyr Pro Ser Tyr Ala Gln Ser Phe Pro Leu Val Ala 610 615 620 Leu Asn Arg Tyr Gln Lys Ile Ser Gln Gly Gln Tyr His Phe Ser Lys 625 630 635 640 Asn Leu Tyr Asn Gly Asn Gly Glu Pro Val Gln Lys Gln Asn Ile 645 650 655 13 5046 DNA Tetrahymena thermophila 13 gaattcatac atttttgata gttcagaaaa taattatttt aatttaattt tttaatcatt 60 ccctcataat ttaataataa ttaaaaatta agactgcata tattaaggca ctttactttt 120 ataaaattaa ttttctacat tataaaatac agaagtattt tattatatat atttttcaaa 180 gtaaatgatt agcttttatt gattaaaatt aatgtgtgat taataatgtt acaatagcaa 240 tataagaaat attagtaaat cattataaga aaatataaac aagatagcat tcatatgcaa 300 aattaatttc tagaaatagt attcaaaaat gaagttaaaa tcctaagtac caactaatct 360 ttttaacata acctcattat tacgaaaata ttattatttt tttagtcact gtttgctaaa 420 tcgtatgatc tttttataaa tctaaaaaaa caaagtaaaa tttaaatatg agtatggctt 480 gtttctaaat ctatttagtg aaagctaatt tcaatttata tgtatttaga gaagcattaa 540 gttaatagga ggggggaaaa cgatgaaaaa ttaaaagtta ttgataagaa ttatttgtaa 600 tattatgttg taagttaaga attaataata ttattaaagg aatagaaagt tcttttaata 660 atattattaa agaaaaattg atatgtttga ggtgatgtca tgacgaaatt acatattatc 720 atgaacaaat caatggaaaa attgactgag ctaaaataaa aattgacgta aagagtttta 780 agtgcgtgtt agatttgaaa aagttaagaa aaatgacatg aatactggga ctttaataat 840 attatatatg taaggaattt attatattaa attcgtttca agttaaattc aaatttggct 900 taatattgtt agcaattaat tgattgtata gtcaacctta gctttaaaaa ccaactctaa 960 cttcaaggtt ttaataatat tattaatcaa ctcataaatt agtaaataag aaaaaagcta 1020 aaactctttc atacatgaag aagatactca taggcttaat tataggtctc tttttattct 1080 caagcgttaa tgccagcgtt aatctcactg aagtctaaaa tgccatctct atctagcaag 1140 gcattaattg ggcagaagta cacaacaata cttggtacta tcctccttac ttaggcgaaa 1200 tgtttatcag tgaatactac ttcgagttac tcgtcttgaa ttggactcat aaatctgctt 1260 tcaacgctac atactttaca gaacgtctcc tctagactta attcgaagat ggttcatggg 1320 agcaagtcag agaacaaaat cttgaaactg gttagttaga tgctactgtc tttaactact 1380 ggtacttaaa gtctattaac aacaatccta aaattgaagc tgctctataa aaggctagaa 1440 aatggatagt tgcttagggt ggtattgaag caactcaaac aatgaccaag tttaagttag 1500 cagccttcgg ttaatacagg taaagtttct ttttcatcaa tattttagaa ataaacaatc 1560 aattttaaat tattctccca tattttgctc aaataataat ttctacttaa ataattagct 1620 tcaactgcaa atataaaaat gaattaattt attataaata aaagcagtaa atataagcaa 1680 atatactaat ttaattagct tattattctg ttaatattta aaagccattt tgactcaata 1740 gcttatttta ttttaaataa ttaaatagtt gggaagattt atggtatgtc ccattgttca 1800 tcttcaagta gaatggaatt ttcaaatata cctacgttaa ggatattgtt gcataatggg 1860 tctatccaca tttaactgcc ttagcttatt tgcgttacta aagaactgtt ttcaatgttc 1920 ctgttgctga tttgagagag ctctggatca attaccctaa taacggtatt aaaatcagtc 1980 caagagaata ctctacactt aatcctgata gcgatctctt gatcttaatg gacgaaatct 2040 tcaaacttaa acaacctctt ggaagtttcg gtgcctacac tatttcaacc ctcttgactt 2100 taatgtcctt caaagacttt tagtcaaagc accctcatct ataccaaaac gaaatacaaa 2160 aggcttacga agacggatac tatttcgttg agtttaacta ctttaacttt agagaagctt 2220 atcacggctc tttggatgat ggtagatggt gggataccat tcttattagt tgggctatgc 2280 ttgaaagtgg ctaagataaa gaaagaatct tccctatcgt ataaaatatg gtcaaagaag 2340 gtctttaacc taaaaaaggt ataggttatg gatatgattt cgaatatgct cctgacactg 2400 atgacactgg attacttctc gttgttatga gttactacaa agaagccttc taaaagtaaa 2460 tccctgaaac tattgaatgg cttttctcta tgcaaaatga cgatggtggc tatccagctt 2520 ttgacaaagg taatttaata ttgataattt attccatttc tttatttaat aaaaataaat 2580 cttttaatta tttcaattga aagatacatt taaataaaat tacaaatgta cttaaaataa 2640 atataatatt attaacactt ctactttatt ttaaaatagg taaaaatgaa gacaatttat 2700 tgttcaagtt tgccttcaat atggctggta ttgctaactc agctgaaatc ttcgatccct 2760 catgtcctga tattactggt cacatcatgg aaggattggg tgagtttgga tatcaagcta 2820 atcatcctta gatttaaaat atgattaaat atcaaagaaa gacttagaac aagtggggat 2880 cttggtaagc tagatggggt gtaaattaca ttatggctgt tggagctgtt gtaccaggtt 2940 tagcaagagt caattacgac ttaaatgaac agtgggtaca aaatagtata aattatttgc 3000 ttaataaata aaataaagat ggtggctttg gtgaatgtgt cctttcttat aatgatcctg 3060 aaaagtggaa tggtataggt aaatctactg tcactcaaac ctcatgggga ctattagctc 3120 ttttagaagt ttataattaa aatgaacaaa ttaagcatgc tgcagataga gctgcttagt 3180 atttattaga ttaattcaaa agagacgata ataccttcta tgatcactcc acaataggaa 3240 caggtcacag aggattactc tatttatagt acccctcata tgcacaatca ttcccattag 3300 tagctttaaa tagatactaa aaaatatctc aaggttaata tcacttctcc aaaaatttgt 3360 acaatggtaa tggagaacct gtataaaaat aaaatatttg aaaattcaat aaactgtatt 3420 ttacatttta aatttatttg tattttttta agttattttt tcataaaata ataaataaat 3480 aaatttaatt tcatttttta tgaatttatt aatacacaaa aattttaatt attaatttta 3540 aaaatcgcat ttattggttt atcaatattt taagtttaaa attattttca gcattttctt 3600 caatatcaaa attcatagtt ttgacatatt aaattattca atgagttttt tatttttgct 3660 tttgtgagta atcaatcttt tttctaaatt tatattgcat taataaacaa atttaagtta 3720 tccattatca cttataatta tttagcatct aaaaattaat gcaaaacttt tttgatgaat 3780 cgattttact aagaattttt atttgttaaa ataagacaaa tgtaatttaa ataaattaat 3840 tccctcttaa attggtattt atttgtataa atctaattca tttaagtaga aattataatt 3900 aataattaaa ttagtaaaat gttatgatat taaacaaata aatagtatat gaatattata 3960 ttttaatcac atctcaatta gtatgctttt cgctgaataa aaagagcctt taataaatag 4020 tagtataatt tctttaaaat atacaatatt tttgaattaa ttggatttta aataaataaa 4080 tatttattaa tttttaaaat ttttgatatt tttaatttaa aacttatttt ttctttcttt 4140 ctattatgct tatttttgat attgaatagt agaagtgatt gatattaata attaatatct 4200 tttttaaaat atcaaagtct taaaaaaaat ataattaatt agttagttag ttacaaaata 4260 tggatagtta gcaacaaatc ggagatttat taactcatta cgaagctgag catttaatag 4320 aaaagttata aatcgttaac atagaagaat atggtagtta aatgtaaaat gctatttagt 4380 tttttagaca ttgttagtca tatcatcgca ctcacttaaa aattatcaat tatttataaa 4440 tagctggttc aagcaagacg aaattcttca aagactcaat atgcaagtat ttattttgcc 4500 attaatcaat tttattaaga aactatttca gcaaaagatc taaattttat ttcaaaaact 4560 cattttacta atatatgcat taaagattta tcaaaaactt ttattattat tatacattta 4620 ttttagatta gaaaaaagaa ttaatatgaa gtaatgagtt ttgaagttat ttgctttact 4680 ttaacttaaa aataatttaa tattatgttt tttcaattaa cattttatca atcaaaatgc 4740 ttaagaaatt aaatttaaag atatttttat atttcaaaaa tattttaggc acatgtcaat 4800 gcaatggtaa aaagtgatga gttcattatg gattctttag tgacttttga taaagtgaag 4860 attttgattt acgatttaat agaaacagaa atttggaaat agaaggtatt gcctttacta 4920 aaaaatcaca tgcttaaaat aaacacatat agaagctata ttgctgttta tcacgaagct 4980 gtagtctgta atttgctaga agtcattatg ttccatagaa ccgctgtcga ctcagctgat 5040 gaattc 5046 14 563 PRT Alicyclobacillus acidoterrestris 14 Ile Ile Ser Gln Arg Arg Glu Asp Gly Thr Trp Ser Ile Tyr Pro Gly 1 5 10 15 Gly Pro Ser Asp Leu Asn Ala Thr Val Glu Ala Tyr Val Ala Leu Lys 20 25 30 Tyr Leu Gly Glu Pro Ala Ser Asp Pro Gln Met Val Gln Ala Lys Glu 35 40 45 Phe Ile Gln Asn Glu Gly Gly Ile Glu Ser Thr Arg Val Phe Thr Arg 50 55 60 Leu Trp Leu Ala Met Val Gly Gln Tyr Pro Trp Asp Lys Leu Pro Val 65 70 75 80 Ile Pro Pro Glu Ile Met His Leu Pro Lys Ser Val Pro Leu Asn Ile 85 90 95 Tyr Asp Phe Ala Ser Trp Ala Arg Ala Thr Ile Val Thr Leu Ser Tyr 100 105 110 Arg His Glu Ser Pro Thr Cys Asp Ala Thr Ser Gly Leu Cys Lys Gly 115 120 125 Ser Gly Ile Val Arg Gly Glu Gly Pro Pro Lys Arg Arg Ser Ala Lys 130 135 140 Gly Gly Asp Ser Gly Phe Phe Val Ala Leu Asp Lys Phe Leu Lys Ala 145 150 155 160 Tyr Asn Lys Trp Pro Ile Gln Pro Gly Arg Lys Ser Gly Glu Gln Lys 165 170 175 Ala Leu Glu Trp Ile Leu Ala His Gln Glu Ala Asp Gly Cys Trp Gly 180 185 190 Gly Ile Gln Pro Pro Trp Phe Tyr Ala Leu Leu Ala Leu Lys Cys Leu 195 200 205 Asn Met Thr Asp His Pro Ala Phe Val Lys Gly Phe Glu Gly Leu Glu 210 215 220 Ala Tyr Gly Val His Thr Ser Asp Gly Gly Trp Met Phe Gln Ala Ser 225 230 235 240 Ile Ser Pro Ile Trp Asp Thr Gly Leu Thr Val Leu Ala Leu Arg Ser 245 250 255 Ala Gly Leu Pro Pro Asp His Pro Ala Leu Ile Lys Ala Gly Glu Trp 260 265 270 Leu Val Ser Lys Gln Ile Leu Lys Asp Gly Asp Trp Lys Val Arg Arg 275 280 285 Arg Lys Ala Lys Pro Gly Gly Trp Ala Phe Glu Phe His Cys Glu Asn 290 295 300 Tyr Pro Asp Val Asp Asp Thr Ala Met Val Val Leu Ala Leu Asn Gly 305 310 315 320 Ile Gln Leu Pro Asp Glu Gly Lys Arg Arg Asp Ala Leu Thr Arg Gly 325 330 335 Phe Arg Trp Leu Arg Glu Met Gln Ser Ser Asn Gly Gly Trp Gly Ala 340 345 350 Tyr Asp Val Asp Asn Thr Arg Gln Leu Thr Lys Ser Asp Ser Ile Phe 355 360 365 Ala Thr Ser Gly Glu Val Ile Asp Pro Pro Ser Glu Asp Val Thr Ala 370 375 380 His Val Leu Glu Cys Phe Gly Ser Phe Gly Tyr Asp Glu Ala Trp Lys 385 390 395 400 Val Ile Arg Lys Ala Val Glu Tyr Leu Lys Ala Gln Gln Arg Pro Asp 405 410 415 Gly Ser Trp Phe Gly Arg Trp Gly Val Asn Tyr Val Tyr Gly Ile Gly 420 425 430 Ala Val Val Pro Gly Leu Lys Ala Val Gly Val Asp Met Arg Glu Pro 435 440 445 Trp Val Gln Lys Ser Leu Asp Trp Leu Val Glu His Gln Asn Glu Asp 450 455 460 Gly Gly Trp Gly Glu Asp Cys Arg Ser Tyr Asp Asp Pro Arg Leu Ala 465 470 475 480 Gly Gln Gly Val Ser Thr Pro Ser Gln Thr Ala Trp Ala Leu Met Ala 485 490 495 Leu Ile Ala Gly Gly Arg Val Glu Ser Asp Ala Val Leu Arg Gly Val 500 505 510 Thr Tyr Leu His Asp Thr Gln Arg Ala Asp Gly Gly Trp Asp Glu Glu 515 520 525 Val Tyr Thr Gly Thr Gly Phe Pro Gly Asp Phe Tyr Leu Ala Tyr Thr 530 535 540 Met Tyr Arg Asp Ile Leu Pro Val Trp Ala Leu Gly Arg Tyr Gln Glu 545 550 555 560 Ala Met Gln 15 559 PRT Alicyclobacillus acidocaldarius 15 Leu Leu His Glu Gln Arg Glu Asp Gly Thr Trp Ala Leu Tyr Pro Gly 1 5 10 15 Gly Pro Pro Asp Leu Asp Thr Thr Ile Glu Ala Tyr Val Ala Leu Lys 20 25 30 Tyr Ile Gly Met Ser Arg Asp Glu Glu Pro Met Gln Lys Ala Leu Arg 35 40 45 Phe Ile Gln Ser Gln Gly Gly Ile Glu Ser Ser Arg Val Phe Thr Arg 50 55 60 Met Trp Leu Ala Leu Val Gly Glu Tyr Pro Trp Glu Lys Val Pro Met 65 70 75 80 Val Pro Pro Glu Ile Met Phe Leu Gly Lys Arg Met Pro Leu Asn Ile 85 90 95 Tyr Glu Phe Gly Ser Trp Ala Arg Ala Thr Val Val Ala Leu Ser Ile 100 105 110 Val Met Ser Arg Gln Pro Val Phe Pro Leu Pro Glu Arg Ala Arg Val 115 120 125 Pro Glu Leu Tyr Glu Thr Asp Val Pro Pro Arg Arg Arg Gly Ala Lys 130 135 140 Gly Gly Gly Gly Trp Ile Phe Asp Ala Leu Asp Arg Ala Leu His Gly 145 150 155 160 Tyr Gln Lys Leu Ser Val His Pro Phe Arg Arg Ala Ala Glu Ile Arg 165 170 175 Ala Leu Asp Trp Leu Leu Glu Arg Gln Ala Gly Asp Gly Ser Trp Gly 180 185 190 Gly Ile Gln Pro Pro Trp Phe Tyr Ala Leu Ile Ala Leu Lys Ile Leu 195 200 205 Asp Met Thr Gln His Pro Ala Phe Ile Lys Gly Trp Glu Gly Leu Glu 210 215 220 Leu Tyr Gly Val Glu Leu Asp Tyr Gly Gly Trp Met Phe Gln Ala Ser 225 230 235 240 Ile Ser Pro Val Trp Asp Thr Gly Leu Ala Val Leu Ala Leu Arg Ala 245 250 255 Ala Gly Leu Pro Ala Asp His Asp Arg Leu Val Lys Ala Gly Glu Trp 260 265 270 Leu Leu Asp Arg Gln Ile Thr Val Pro Gly Asp Trp Ala Val Lys Arg 275 280 285 Pro Asn Leu Lys Pro Gly Gly Phe Ala Phe Gln Phe Asp Asn Val Tyr 290 295 300 Tyr Pro Asp Val Asp Asp Thr Ala Val Val Val Trp Ala Leu Asn Thr 305 310 315 320 Leu Arg Leu Pro Asp Glu Arg Arg Arg Arg Asp Ala Met Thr Lys Gly 325 330 335 Phe Arg Trp Ile Val Gly Met Gln Ser Ser Asn Gly Gly Trp Gly Ala 340 345 350 Tyr Asp Val Asp Asn Thr Ser Asp Leu Pro Asn His Ile Pro Phe Cys 355 360 365 Asp Phe Gly Glu Val Thr Asp Pro Pro Ser Glu Asp Val Thr Ala His 370 375 380 Val Leu Glu Cys Phe Gly Ser Phe Gly Tyr Asp Asp Ala Trp Lys Val 385 390 395 400 Ile Arg Arg Ala Val Glu Tyr Leu Lys Arg Glu Gln Lys Pro Asp Gly 405 410 415 Ser Trp Phe Gly Arg Trp Gly Val Asn Tyr Leu Tyr Gly Thr Gly Ala 420 425 430 Val Val Ser Ala Leu Lys Ala Val Gly Ile Asp Thr Arg Glu Pro Tyr 435 440 445 Ile Gln Lys Ala Leu Asp Trp Val Glu Gln His Gln Asn Pro Asp Gly 450 455 460 Gly Trp Gly Glu Asp Cys Arg Ser Tyr Glu Asp Pro Ala Tyr Ala Gly 465 470 475 480 Lys Gly Ala Ser Thr Pro Ser Gln Thr Ala Trp Ala Leu Met Ala Leu 485 490 495 Ile Ala Gly Gly Arg Ala Glu Ser Glu Ala Ala Arg Arg Gly Val Gln 500 505 510 Tyr Leu Val Glu Thr Gln Arg Pro Asp Gly Gly Trp Asp Glu Pro Tyr 515 520 525 Tyr Thr Gly Thr Gly Phe Pro Gly Asp Phe Tyr Leu Gly Tyr Thr Met 530 535 540 Tyr Arg His Val Phe Pro Thr Leu Ala Leu Gly Arg Tyr Lys Gln 545 550 555 16 630 PRT Alicyclobacillus acidocaldarius 16 Ala Glu Gln Leu Val Glu Ala Pro Ala Tyr Ala Arg Thr Leu Asp Arg 1 5 10 15 Ala Val Glu Tyr Leu Leu Ser Cys Gln Lys Asp Glu Gly Tyr Trp Trp 20 25 30 Gly Pro Leu Leu Ser Asn Val Thr Met Glu Ala Glu Tyr Val Leu Leu 35 40 45 Cys His Ile Leu Asp Arg Val Asp Arg Asp Arg Met Glu Lys Ile Arg 50 55 60 Arg Tyr Leu Leu His Glu Gln Arg Glu Asp Gly Thr Trp Ala Leu Tyr 65 70 75 80 Pro Gly Gly Pro Pro Asp Leu Asp Thr Thr Ile Glu Ala Tyr Val Ala 85 90 95 Leu Lys Tyr Ile Gly Met Ser Arg Asp Glu Glu Pro Met Gln Lys Ala 100 105 110 Leu Arg Phe Ile Gln Ser Gln Gly Gly Ile Glu Ser Ser Arg Val Phe 115 120 125 Thr Arg Met Trp Leu Ala Leu Val Gly Glu Tyr Pro Trp Glu Lys Val 130 135 140 Pro Met Val Pro Pro Glu Ile Met Phe Leu Gly Lys Arg Met Pro Leu 145 150 155 160 Asn Ile Tyr Glu Phe Gly Ser Trp Ala Arg Ala Thr Val Val Ala Leu 165 170 175 Ser Ile Val Met Ser Arg Gln Pro Val Phe Pro Leu Pro Glu Arg Ala 180 185 190 Arg Val Pro Glu Leu Tyr Glu Thr Asp Val Pro Pro Arg Arg Arg Gly 195 200 205 Ala Lys Gly Gly Gly Gly Trp Ile Phe Asp Ala Leu Asp Arg Ala Leu 210 215 220 His Gly Tyr Gln Lys Leu Ser Val His Pro Phe Arg Arg Ala Ala Glu 225 230 235 240 Ile Arg Ala Leu Asp Trp Leu Leu Glu Arg Gln Ala Gly Asp Gly Ser 245 250 255 Trp Gly Gly Ile Gln Pro Pro Trp Phe Tyr Ala Leu Ile Ala Leu Lys 260 265 270 Ile Leu Asp Met Thr Gln His Pro Ala Phe Ile Lys Gly Trp Glu Gly 275 280 285 Leu Glu Leu Tyr Gly Val Glu Leu Asp Tyr Gly Gly Trp Met Phe Gln 290 295 300 Ala Ser Ile Ser Pro Val Trp Asp Thr Gly Leu Ala Val Leu Ala Leu 305 310 315 320 Arg Ala Ala Gly Leu Pro Ala Asp His Asp Arg Leu Val Lys Ala Gly 325 330 335 Glu Trp Leu Leu Asp Arg Gln Ile Thr Val Pro Gly Asp Trp Ala Val 340 345 350 Lys Arg Pro Asn Leu Lys Pro Gly Gly Phe Ala Phe Gln Phe Asp Asn 355 360 365 Val Tyr Tyr Pro Asp Val Asp Asp Thr Ala Val Val Val Trp Ala Leu 370 375 380 Asn Thr Leu Arg Leu Pro Asp Glu Arg Arg Arg Arg Asp Ala Met Thr 385 390 395 400 Lys Gly Phe Arg Trp Ile Val Gly Met Gln Ser Ser Asn Gly Gly Trp 405 410 415 Gly Ala Tyr Asp Val Asp Asn Thr Ser Asp Leu Pro Asn His Ile Pro 420 425 430 Phe Cys Asp Phe Gly Glu Val Thr Asp Pro Pro Ser Glu Asp Val Thr 435 440 445 Ala His Val Leu Glu Cys Phe Gly Ser Phe Gly Tyr Asp Asp Ala Trp 450 455 460 Lys Val Ile Arg Arg Ala Val Glu Tyr Leu Lys Arg Glu Gln Lys Pro 465 470 475 480 Asp Gly Ser Trp Phe Gly Arg Trp Gly Val Asn Tyr Leu Tyr Gly Thr 485 490 495 Gly Ala Val Val Ser Ala Leu Lys Ala Val Gly Ile Asp Thr Arg Glu 500 505 510 Pro Tyr Ile Gln Lys Ala Leu Asp Trp Val Glu Gln His Gln Asn Pro 515 520 525 Asp Gly Gly Trp Gly Glu Asp Cys Arg Ser Tyr Glu Asp Pro Ala Tyr 530 535 540 Ala Gly Lys Gly Ala Ser Thr Pro Ser Gln Thr Ala Trp Ala Leu Met 545 550 555 560 Ala Leu Ile Ala Gly Gly Arg Ala Glu Ser Glu Ala Ala Arg Arg Gly 565 570 575 Val Gln Tyr Leu Val Glu Thr Gln Arg Pro Asp Gly Gly Trp Asp Glu 580 585 590 Pro Tyr Tyr Thr Gly Thr Gly Phe Pro Gly Asp Phe Tyr Leu Gly Tyr 595 600 605 Thr Met Tyr Arg His Val Phe Pro Thr Leu Ala Leu Gly Arg Tyr Lys 610 615 620 Gln Ala Ile Glu Arg Arg 625 630 17 634 PRT Alicyclobacillus acidocaldarius 17 Met Thr Lys Gln Leu Leu Asp Thr Pro Met Val Gln Ala Thr Leu Glu 1 5 10 15 Ala Gly Val Ala His Leu Leu Arg Arg Gln Ala Pro Asp Gly Tyr Trp 20 25 30 Trp Ala Pro Leu Leu Ser Asn Val Cys Met Glu Ala Glu Tyr Val Leu 35 40 45 Leu Cys His Cys Leu Gly Lys Lys Asn Pro Glu Arg Glu Ala Gln Ile 50 55 60 Arg Lys Tyr Ile Ile Ser Gln Arg Arg Glu Asp Gly Thr Trp Ser Ile 65 70 75 80 Tyr Pro Gly Gly Pro Ser Asp Leu Asn Ala Thr Val Glu Ala Tyr Val 85 90 95 Ala Leu Lys Tyr Leu Gly Glu Pro Ala Ser Asp Pro Gln Met Val Gln 100 105 110 Ala Lys Glu Phe Ile Gln Asn Glu Gly Gly Ile Glu Ser Thr Arg Val 115 120 125 Phe Thr Arg Leu Trp Leu Ala Met Val Gly Gln Tyr Pro Trp Asp Lys 130 135 140 Leu Pro Val Ile Pro Pro Glu Ile Met His Leu Pro Lys Ser Val Pro 145 150 155 160 Leu Asn Ile Tyr Asp Phe Ala Ser Trp Ala Arg Ala Thr Ile Val Thr 165 170 175 Leu Ser Tyr Arg His Glu Ser Pro Thr Cys Asp Ala Thr Ser Gly Leu 180 185 190 Cys Lys Gly Ser Gly Ile Val Arg Gly Glu Gly Pro Pro Lys Arg Arg 195 200 205 Ser Ala Lys Gly Gly Asp Ser Gly Phe Phe Val Ala Leu Asp Lys Phe 210 215 220 Leu Lys Ala Tyr Asn Lys Trp Pro Ile Gln Pro Gly Arg Lys Ser Gly 225 230 235 240 Glu Gln Lys Ala Leu Glu Trp Ile Leu Ala His Gln Glu Ala Asp Gly 245 250 255 Cys Trp Gly Gly Ile Gln Pro Pro Trp Phe Tyr Ala Leu Leu Ala Leu 260 265 270 Lys Cys Leu Asn Met Thr Asp His Pro Ala Phe Val Lys Gly Phe Glu 275 280 285 Gly Leu Glu Ala Tyr Gly Val His Thr Ser Asp Gly Gly Trp Met Phe 290 295 300 Gln Ala Ser Ile Ser Pro Ile Trp Asp Thr Gly Leu Thr Val Leu Ala 305 310 315 320 Leu Arg Ser Ala Gly Leu Pro Pro Asp His Pro Ala Leu Ile Lys Ala 325 330 335 Gly Glu Trp Leu Val Ser Lys Gln Ile Leu Lys Asp Gly Asp Trp Lys 340 345 350 Val Arg Arg Arg Lys Ala Lys Pro Gly Gly Trp Ala Phe Glu Phe His 355 360 365 Cys Glu Asn Tyr Pro Asp Val Asp Asp Thr Ala Met Val Val Leu Ala 370 375 380 Leu Asn Gly Ile Gln Leu Pro Asp Glu Gly Lys Arg Arg Asp Ala Leu 385 390 395 400 Thr Arg Gly Phe Arg Trp Leu Arg Glu Met Gln Ser Ser Asn Gly Gly 405 410 415 Trp Gly Ala Tyr Asp Val Asp Asn Thr Arg Gln Leu Thr Lys Ser Asp 420 425 430 Ser Ile Phe Ala Thr Ser Gly Glu Val Ile Asp Pro Pro Ser Glu Asp 435 440 445 Val Thr Ala His Val Leu Glu Cys Phe Gly Ser Phe Gly Tyr Asp Glu 450 455 460 Ala Trp Lys Val Ile Arg Lys Ala Val Glu Tyr Leu Lys Ala Gln Gln 465 470 475 480 Arg Pro Asp Gly Ser Trp Phe Gly Arg Trp Gly Val Asn Tyr Val Tyr 485 490 495 Gly Ile Gly Ala Val Val Pro Gly Leu Lys Ala Val Gly Val Asp Met 500 505 510 Arg Glu Pro Trp Val Gln Lys Ser Leu Asp Trp Leu Val Glu His Gln 515 520 525 Asn Glu Asp Gly Gly Trp Gly Glu Asp Cys Arg Ser Tyr Asp Asp Pro 530 535 540 Arg Leu Ala Gly Gln Gly Val Ser Thr Pro Ser Gln Thr Ala Trp Ala 545 550 555 560 Leu Met Ala Leu Ile Ala Gly Gly Arg Val Glu Ser Asp Ala Val Leu 565 570 575 Arg Gly Val Thr Tyr Leu His Asp Thr Gln Arg Ala Asp Gly Gly Trp 580 585 590 Asp Glu Glu Val Tyr Thr Gly Thr Gly Phe Pro Gly Asp Phe Tyr Leu 595 600 605 Ala Tyr Thr Met Tyr Arg Asp Ile Leu Pro Val Trp Ala Leu Gly Arg 610 615 620 Tyr Gln Glu Ala Met Gln Arg Ile Arg Gly 625 630 18 647 PRT Synechocystis sp. 18 Met Val Ile Ala Ala Ser Pro Ser Val Pro Cys Pro Ser Thr Glu Gln 1 5 10 15 Val Arg Gln Ala Ile Ala Ala Ser Arg Asp Phe Leu Leu Ser Glu Gln 20 25 30 Tyr Ala Asp Gly Tyr Trp Trp Ser Glu Leu Glu Ser Asn Val Thr Ile 35 40 45 Thr Ala Glu Val Val Ile Leu His Lys Ile Trp Gly Thr Ala Ala Gln 50 55 60 Arg Pro Leu Glu Lys Ala Lys Asn Tyr Leu Leu Gln Gln Gln Arg Asp 65 70 75 80 His Gly Gly Trp Glu Leu Tyr Tyr Gly Asp Gly Gly Glu Leu Ser Thr 85 90 95 Ser Val Glu Ala Tyr Thr Ala Leu Arg Ile Leu Gly Val Pro Ala Thr 100 105 110 Asp Pro Ala Leu Val Lys Ala Lys Asn Phe Ile Val Gly Arg Gly Gly 115 120 125 Ile Ser Lys Ser Arg Ile Phe Thr Lys Met His Leu Ala Leu Ile Gly 130 135 140 Cys Tyr Asp Trp Arg Gly Thr Pro Ser Ile Pro Pro Trp Val Met Leu 145 150 155 160 Leu Pro Asn Asn Phe Phe Phe Asn Ile Tyr Glu Met Ser Ser Trp Ala 165 170 175 Arg Ser Ser Thr Val Pro Leu Met Ile Val Cys Asp Gln Lys Pro Val 180 185 190 Tyr Asp Ile Ala Gln Gly Leu Arg Val Asp Glu Leu Tyr Ala Glu Gly 195 200 205 Met Glu Asn Val Gln Tyr Lys Leu Pro Glu Ser Gly Thr Ile Trp Asp 210 215 220 Ile Phe Ile Gly Leu Asp Ser Leu Phe Lys Leu Gln Glu Gln Ala Lys 225 230 235 240 Val Val Pro Phe Arg Glu Gln Gly Leu Ala Leu Ala Glu Lys Trp Ile 245 250 255 Leu Glu Arg Gln Glu Val Ser Gly Asp Trp Gly Gly Ile Ile Pro Ala 260 265 270 Met Leu Asn Ser Leu Leu Ala Leu Lys Val Leu Gly Tyr Asp Val Asn 275 280 285 Asp Leu Tyr Val Gln Arg Gly Leu Ala Ala Ile Asp Asn Phe Ala Val 290 295 300 Glu Thr Glu Asp Ser Tyr Ala Ile Gln Ala Cys Val Ser Pro Val Trp 305 310 315 320 Asp Thr Ala Trp Val Val Arg Ala Leu Ala Glu Ala Asp Leu Gly Lys 325 330 335 Asp His Pro Ala Leu Val Lys Ala Gly Gln Trp Leu Leu Asp Lys Gln 340 345 350 Ile Leu Thr Tyr Gly Asp Trp Gln Ile Lys Asn Pro His Gly Glu Pro 355 360 365 Gly Ala Trp Ala Phe Glu Phe Asp Asn Asn Phe Tyr Pro Asp Ile Asp 370 375 380 Asp Thr Cys Val Val Met Met Ala Leu Gln Gly Ile Thr Leu Pro Asp 385 390 395 400 Glu Glu Arg Lys Gln Gly Ala Ile Asn Lys Ala Leu Gln Trp Ile Ala 405 410 415 Thr Met Gln Cys Lys Thr Gly Gly Trp Ala Ala Phe Asp Ile Asp Asn 420 425 430 Asp Gln Asp Trp Leu Asn Gln Leu Pro Tyr Gly Asp Leu Lys Ala Met 435 440 445 Ile Asp Pro Ser Thr Ala Asp Ile Thr Ala Arg Val Val Glu Met Leu 450 455 460 Gly Ala Cys Gly Leu Thr Met Asp Ser Pro Arg Val Glu Arg Gly Leu 465 470 475 480 Thr Tyr Leu Leu Gln Glu Gln Glu Gln Asp Gly Ser Trp Phe Gly Arg 485 490 495 Trp Gly Val Asn Tyr Leu Tyr Gly Thr Ser Gly Ala Leu Ser Ala Leu 500 505 510 Ala Ile Tyr Asp Ala Gln Arg Phe Ala Pro Gln Ile Lys Thr Ala Ile 515 520 525 Ala Trp Leu Leu Ser Cys Gln Asn Ala Asp Gly Gly Trp Gly Glu Thr 530 535 540 Cys Glu Ser Tyr Lys Asn Lys Gln Leu Lys Gly Gln Gly Asn Ser Thr 545 550 555 560 Ala Ser Gln Thr Ala Trp Ala Leu Ile Gly Leu Leu Asp Ala Leu Lys 565 570 575 Tyr Leu Pro Ser Leu Gly Gln Asp Ala Lys Leu Thr Thr Ala Ile Glu 580 585 590 Gly Gly Val Ala Phe Leu Val Gln Gly Gln Thr Pro Lys Gly Thr Trp 595 600 605 Glu Glu Ala Glu Tyr Thr Gly Thr Gly Phe Pro Cys His Phe Tyr Ile 610 615 620 Arg Tyr His Tyr Tyr Arg Gln Tyr Phe Pro Leu Ile Ala Leu Ala Arg 625 630 635 640 Tyr Ser His Leu Gln Ala Ser 645 19 680 PRT Streptomyces coelicolor 19 Met Thr Ala Thr Thr Asp Gly Ser Thr Gly Ala Ser Leu Arg Pro Leu 1 5 10 15 Ala Ala Ser Ala Ser Asp Thr Asp Ile Thr Ile Pro Ala Ala Ala Ala 20 25 30 Gly Val Pro Glu Ala Ala Ala Arg Ala Thr Arg Arg Ala Thr Asp Phe 35 40 45 Leu Leu Ala Lys Gln Asp Ala Glu Gly Trp Trp Lys Gly Asp Leu Glu 50 55 60 Thr Asn Val Thr Met Asp Ala Glu Asp Leu Leu Leu Arg Gln Phe Leu 65 70 75 80 Gly Ile Gln Asp Glu Glu Thr Thr Arg Ala Ala Ala Leu Phe Ile Arg 85 90 95 Gly Glu Gln Arg Glu Asp Gly Thr Trp Ala Thr Phe Tyr Gly Gly Pro 100 105 110 Gly Glu Leu Ser Thr Thr Ile Glu Ala Tyr Val Ala Leu Arg Leu Ala 115 120 125 Gly Asp Ser Pro Glu Ala Pro His Met Ala Arg Ala Ala Glu Trp Ile 130 135 140 Arg Ser Arg Gly Gly Ile Ala Ser Ala Arg Val Phe Thr Arg Ile Trp 145 150 155 160 Leu Ala Leu Phe Gly Trp Trp Lys Trp Asp Asp Leu Pro Glu Leu Pro 165 170 175 Pro Glu Leu Ile Tyr Phe Pro Thr Trp Val Pro Leu Asn Ile Tyr Asp 180 185 190 Phe Gly Cys Trp Ala Arg Gln Thr Ile Val Pro Leu Thr Ile Val Ser 195 200 205 Ala Lys Arg Pro Val Arg Pro Ala Pro Phe Pro Leu Asp Glu Leu His 210 215 220 Thr Asp Pro Ala Arg Pro Asn Pro Pro Arg Pro Leu Ala Pro Val Ala 225 230 235 240 Ser Trp Asp Gly Ala Phe Gln Arg Ile Asp Lys Ala Leu His Ala Tyr 245 250 255 Arg Lys Val Ala Pro Arg Arg Leu Arg Arg Ala Ala Met Asn Ser Ala 260 265 270 Ala Arg Trp Ile Ile Glu Arg Gln Glu Asn Asp Gly Cys Trp Gly Gly 275 280 285 Ile Gln Pro Pro Ala Val Tyr Ser Val Ile Ala Leu Tyr Leu Leu Gly 290 295 300 Tyr Asp Leu Glu His Pro Val Met Arg Ala Gly Leu Glu Ser Leu Asp 305 310 315 320 Arg Phe Ala Val Trp Arg Glu Asp Gly Ala Arg Met Ile Glu Ala Cys 325 330 335 Gln Ser Pro Val Trp Asp Thr Cys Leu Ala Thr Ile Ala Leu Ala Asp 340 345 350 Ala Gly Val Pro Glu Asp His Pro Gln Leu Val Lys Ala Ser Asp Trp 355 360 365 Met Leu Gly Glu Gln Ile Val Arg Pro Gly Asp Trp Ser Val Lys Arg 370 375 380 Pro Gly Leu Pro Pro Gly Gly Trp Ala Phe Glu Phe His Asn Asp Asn 385 390 395 400 Tyr Pro Asp Ile Asp Asp Thr Ala Glu Val Val Leu Ala Leu Arg Arg 405 410 415 Val Arg His His Asp Pro Glu Arg Val Glu Lys Ala Ile Gly Arg Gly 420 425 430 Val Arg Trp Asn Leu Gly Met Gln Ser Lys Asn Gly Ala Trp Gly Ala 435 440 445 Phe Asp Val Asp Asn Thr Ser Ala Phe Pro Asn Arg Leu Pro Phe Cys 450 455 460 Asp Phe Gly Glu Val Ile Asp Pro Pro Ser Ala Asp Val Thr Ala His 465 470 475 480 Val Val Glu Met Leu Ala Val Glu Gly Leu Ala His Asp Pro Arg Thr 485 490 495 Arg Arg Gly Ile Gln Trp Leu Leu Asp Ala Gln Glu Thr Asp Gly Ser 500 505 510 Trp Phe Gly Arg Trp Gly Val Asn Tyr Val Tyr Gly Thr Gly Ser Val 515 520 525 Ile Pro Ala Leu Thr Ala Ala Gly Leu Pro Thr Ser His Pro Ala Ile 530 535 540 Arg Arg Ala Val Arg Trp Leu Glu Ser Val Gln Asn Glu Asp Gly Gly 545 550 555 560 Trp Gly Glu Asp Leu Arg Ser Tyr Arg Tyr Val Arg Glu Trp Ser Gly 565 570 575 Arg Gly Ala Ser Thr Ala Ser Gln Thr Gly Trp Ala Leu Met Ala Leu 580 585 590 Leu Ala Ala Gly Glu Arg Asp Ser Lys Ala Val Glu Arg Gly Val Ala 595 600 605 Trp Leu Ala Ala Thr Gln Arg Glu Asp Gly Ser Trp Asp Glu Pro Tyr 610 615 620 Phe Thr Gly Thr Gly Phe Pro Trp Asp Phe Ser Ile Asn Tyr Asn Leu 625 630 635 640 Tyr Arg Gln Val Phe Pro Leu Thr Ala Leu Gly Arg Tyr Val His Gly 645 650 655 Glu Pro Phe Ala Lys Lys Pro Arg Ala Ala Asp Ala Pro Ala Glu Ala 660 665 670 Ala Pro Ala Glu Val Lys Gly Ser 675 680 20 757 PRT Arabidopsis thaliana 20 Met Trp Lys Leu Lys Ile Gly Lys Gly Asn Gly Glu Asp Pro His Leu 1 5 10 15 Phe Ser Ser Asn Asn Phe Val Gly Arg Gln Thr Trp Lys Phe Asp His 20 25 30 Lys Ala Gly Ser Pro Glu Glu Arg Ala Ala Val Glu Glu Ala Arg Arg 35 40 45 Gly Phe Leu Asp Asn Arg Phe Arg Val Lys Gly Cys Ser Asp Leu Leu 50 55 60 Trp Arg Met Gln Phe Leu Arg Glu Lys Lys Phe Glu Gln Gly Ile Pro 65 70 75 80 Gln Leu Lys Ala Thr Asn Ile Glu Glu Ile Thr Tyr Glu Thr Thr Thr 85 90 95 Asn Ala Leu Arg Arg Gly Val Arg Tyr Phe Thr Ala Leu Gln Ala Ser 100 105 110 Asp Gly His Trp Pro Gly Glu Ile Thr Gly Pro Leu Phe Phe Leu Pro 115 120 125 Pro Leu Ile Phe Cys Leu Tyr Ile Thr Gly His Leu Glu Glu Val Phe 130 135 140 Asp Ala Glu His Arg Lys Glu Met Leu Arg His Ile Tyr Cys His Gln 145 150 155 160 Asn Glu Asp Gly Gly Trp Gly Leu His Ile Glu Ser Lys Ser Val Met 165 170 175 Phe Cys Thr Val Leu Asn Tyr Ile Cys Leu Arg Met Leu Gly Glu Asn 180 185 190 Pro Glu Gln Asp Ala Cys Lys Arg Ala Arg Gln Trp Ile Leu Asp Arg 195 200 205 Gly Gly Val Ile Phe Ile Pro Ser Trp Gly Lys Phe Trp Leu Ser Ile 210 215 220 Leu Gly Val Tyr Asp Trp Ser Gly Thr Asn Pro Thr Pro Pro Glu Leu 225 230 235 240 Leu Met Leu Pro Ser Phe Leu Pro Ile His Pro Gly Lys Ile Leu Cys 245 250 255 Tyr Ser Arg Met Val Ser Ile Pro Met Ser Tyr Leu Tyr Gly Lys Arg 260 265 270 Phe Val Gly Pro Ile Thr Pro Leu Ile Leu Leu Leu Arg Glu Glu Leu 275 280 285 Tyr Leu Glu Pro Tyr Glu Glu Ile Asn Trp Lys Lys Ser Arg Arg Leu 290 295 300 Tyr Ala Lys Glu Asp Met Tyr Tyr Ala His Pro Leu Val Gln Asp Leu 305 310 315 320 Leu Ser Asp Thr Leu Gln Asn Phe Val Glu Pro Leu Leu Thr Arg Trp 325 330 335 Pro Leu Asn Lys Leu Val Arg Glu Lys Ala Leu Gln Leu Thr Met Lys 340 345 350 His Ile His Tyr Glu Asp Glu Asn Ser His Tyr Ile Thr Ile Gly Cys 355 360 365 Val Glu Lys Val Leu Cys Met Leu Ala Cys Trp Val Glu Asn Pro Asn 370 375 380 Gly Asp Tyr Phe Lys Lys His Leu Ala Arg Ile Pro Asp Tyr Met Trp 385 390 395 400 Val Ala Glu Asp Gly Met Lys Met Gln Ser Phe Gly Cys Gln Leu Trp 405 410 415 Asp Thr Gly Phe Ala Ile Gln Ala Leu Leu Ala Ser Asn Leu Pro Asp 420 425 430 Glu Thr Asp Asp Ala Leu Lys Arg Gly His Asn Tyr Ile Lys Ala Ser 435 440 445 Gln Val Arg Glu Asn Pro Ser Gly Asp Phe Arg Ser Met Tyr Arg His 450 455 460 Ile Ser Lys Gly Ala Trp Thr Phe Ser Asp Arg Asp His Gly Trp Gln 465 470 475 480 Val Ser Asp Cys Thr Ala Glu Ala Leu Lys Cys Cys Leu Leu Leu Ser 485 490 495 Met Met Ser Ala Asp Ile Gly Gly Gln Lys Ile Asp Asp Glu Gln Leu 500 505 510 Tyr Asp Ser Val Asn Leu Leu Leu Ser Leu Gln Ser Gly Asn Gly Gly 515 520 525 Val Asn Ala Trp Glu Pro Ser Arg Ala Tyr Lys Trp Leu Glu Leu Leu 530 535 540 Asn Pro Thr Glu Phe Met Ala Asn Thr Met Val Glu Arg Glu Phe Val 545 550 555 560 Glu Cys Thr Ser Ser Val Ile Gln Ala Leu Asp Leu Phe Arg Lys Leu 565 570 575 Tyr Pro Asp His Arg Lys Lys Glu Ile Asn Arg Ser Ile Glu Lys Ala 580 585 590 Val Gln Phe Ile Gln Asp Asn Gln Thr Pro Asp Gly Ser Trp Tyr Gly 595 600 605 Asn Trp Gly Val Cys Phe Ile Tyr Ala Thr Trp Phe Ala Leu Gly Gly 610 615 620 Leu Ala Ala Ala Gly Glu Thr Tyr Asn Asp Cys Leu Ala Met Arg Asn 625 630 635 640 Gly Val His Phe Leu Leu Thr Thr Gln Arg Asp Asp Gly Gly Trp Gly 645 650 655 Glu Ser Tyr Leu Ser Cys Ser Glu Gln Arg Tyr Ile Pro Ser Glu Gly 660 665 670 Glu Arg Ser Asn Leu Val Gln Thr Ser Trp Ala Met Met Ala Leu Ile 675 680 685 His Thr Gly Gln Ala Glu Arg Asp Leu Thr Pro Leu His Arg Ala Ala 690 695 700 Lys Leu Ile Ile Asn Ser Gln Leu Glu Asn Gly Asp Phe Pro Gln Gln 705 710 715 720 Glu Ile Val Gly Ala Phe Met Asn Thr Cys Met Leu His Tyr Ala Thr 725 730 735 Tyr Arg Asn Thr Phe Pro Leu Trp Ala Leu Ala Glu Tyr Arg Lys Val 740 745 750 Val Phe Ile Val Asn 755 21 18 PRT Artificial Sequence Description of Artificial Sequence QW-motif 21 Xaa Xaa Xaa Xaa Xaa Leu Xaa Xaa Xaa Gln Xaa Xaa Xaa Xaa Xaa Gly 1 5 10 15 Xaa Trp 22 6 PRT Artificial Sequence Description of Artificial Sequence conserved motif 22 Asp Xaa Asp Asp Thr Ala 1 5 23 6 PRT Artificial Sequence Description of Artificial Sequence conserved motif 23 Asp Thr Asp Asp Thr Gly 1 5 

We claim:
 1. An isolated nucleic acid comprising a nucleic acid sequence encoding a polypeptide or functional variant thereof comprising the amino acid sequence of SEQ ID No.
 12. 2. The isolated nucleic acid of claim 1 wherein said nucleic acid comprises the nucleic acid sequence of SEQ ID No.
 11. 3. The isolated nucleic acid of claim 1 wherein said nucleic acid comprises at least 8 nucleotides of SEQ ID No.
 11. 4. The isolated nucleic acid of claim 1, wherein said nucleic acid is selected from the group consisting of DNA, RNA, and double-stranded DNA.
 5. The isolated nucleic acid of claim 1 wherein said nucleic acid comprises the nucleic acid sequence of SEQ ID No.
 13. 6. The isolated nucleic acid of claim 5, wherein said nucleic acid comprises one or more non-coding sequences.
 7. The isolated nucleic acid of claim 1, wherein said nucleic acid is antisense.
 8. A vector comprising the isolated nucleic acid of claim
 1. 9. The vector of claim 8, wherein said vector is an expression vector.
 10. An isolated host cell comprising the vector of claim
 8. 11. The isolated host cell of claim 10, wherein said host cell is a protozoa.
 12. The isolated host cell of claim 11, wherein said host cell is a ciliate.
 13. A method of producing the isolated nucleic acid of claim 1 comprising the step of chemically synthesizing said nucleic acid.
 14. A method of producing the isolated nucleic acid of claim 1 comprising the step of isolating said nucleic acid from a gene library by screening said library with a probe.
 15. An isolated polypeptide or functional variant thereof comprising the amino acid sequence of SEQ ID No.
 12. 16. The isolated polypeptide of claim 15 wherein said polypeptide comprises at least 6 amino acids of SEQ ID No.
 12. 17. A method of producing a polypeptide comprising culturing a host cell of claim 10, under conditions sufficient for the production of said polypeptide and recovering said polypeptide from the culture.
 18. The method of claim 17, wherein said host cell is a protozoa.
 19. The method of claim 18, wherein said protozoa is a ciliate.
 20. An antibody capable of binding the polypeptide of SEQ ID No.
 12. 21. A method of producing said antibody of claim 20 comprising the steps of immunizing a mammal with said polypeptide and isolating said antibodies.
 22. The isolated nucleic acid of claim 1, wherein said nucleic acid is used to identify polypeptide variants comprising the steps of screening a gene library with said nucleic acid and isolating said variant.
 23. A method of enriching the saturated fatty acid content in a host cell comprising the step of inactivating the transcription of the nucleic acid of claim 1 in said host cell.
 24. The method of claim 23, wherein said nucleic acid is inactivated by an antisense nucleic acid.
 25. The method of claim 23, wherein said nucleic acid is inactivated by a method selected from the group comprising deletion of said nucleic acid, insertion of a nucleic acid, and mutation of said nucleic acid.
 26. The method of claim 25, wherein said nucleic acid is replaced with one or more selectable markers.
 27. The method of claim 23, wherein said saturated fatty acid is squalene.
 28. The isolated nucleic acid of claim 1, wherein said nucleic acid is used to produce cyclic triterpenoids.
 29. The isolated nucleic acid of claim 28, wherein said cyclic triterpenoid is pentacyclic triterpenoid.
 30. The isolated nucleic acid of claim 28, wherein said cyclic triterpenoid is tetrahymanol. 